January

Garnet has been the birthstone for January since the 15th century, at least. With a Mohs hardness of 6.5 to 7.5, it can be faceted into beautiful gemstones that wear well in jewelry. Since the term “garnet” actually refers to a group of nesosilicate gems, those born in this month can choose from a rainbow of colors.

The most common members are red almandine, an iron-aluminum silicate; red pyrope, a magnesium aluminum silicate; orange-yellow spessartine, a manganese aluminum silicate; the yellow or green varieties of andradite, a calcium-iron silicate; predominately green grossular, a calcium-aluminum silicate; and rare, bright-green uvarovite, a calcium chromium silicate.

February

From the 15th century to the present, amethyst has been the preferred birthstone for February. Amethyst belongs to a mineral family that can compete with garnet for diversity of color: quartz.

Pure quartz is colorless, as exemplified by Herkimer diamonds. The causes of amethyst’s shades of pale violet to rich purple are radiation and the inclusion of iron impurities and trace elements.

As a rule, amethyst crystals are short and stubby, and occur in large numbers, often filling a large vug a hollow petrified tree section, or lining the inside of a geode. Fine crystals that are large enough to produce a faceted gem of over 20 carats are rare.

March

The current choice of a birthstone for March is aquamarine. Aquamarine is a variety of beryl (Mohs 7.5-8). Its name was derived from the fact that the beautiful, transparent, blue-green coloration of the gem resembles that of seawater. It can be found in translucent to transparent crystals that form in the hexagonal system. The six-sided crystals are often striated lengthwise.

Aquamarine develops in metamorphic rocks and, more often, in pegmatites.

April

Before 1900, a person with an April birthday had two choices of birthstone: diamond or sapphire. During the 20th century, however, diamonds became the preferred stone.

Diamond, a mineral consisting of pure carbon, heads the list of all gemstones for its beauty and hardness. A 10 on the Mohs Scale of Hardness, it is resistant to scratching and is an ideal gem to set in rings. Its hardness results from the arrangement of its atoms in cubes.

All diamonds have slightly rounded faces, and they’re so smooth they feel greasy to the touch. They can be colorless and water clear to blue, pink, yellow, brown, green or black, and transparent or translucent. They shine with an adamantine luster when held to the light.

May

There were two choices for May birthstones for several hundred years: emerald and agate. The popularity of agate seems to have waned at the turn of the 20th century, so emerald is now the favorite. It’s the green member of the beryl family of gemstones. The color varies from bright green to pale green and, sometimes, darker shades of blue-green.

Fine emeralds have a velvety surface appearance and, in the better stones, an even distribution of color. One bad trait of emeralds is a tendency to have inclusions. It’s rare to find an emerald without some slight imperfection. This in no way deters from the beauty of this gemstone, though. It can also be one way of determining whether an emerald is a simulated gem or the real thing, as manmade stones have no imperfections.

June

The contemporary choices for June are pearl, moonstone and alexandrite. Of course, a pearl is the organic product of marine bivalves and not a mineral.

Moonstone is a variety of feldspar that shows adularescence, or schiller, an optical effect that produces a milky luster with a bluish tinge that appears to move across the stone when it is tilted. The phenomenon is named after the feldspar variety adularia.

Alexandrite is a color-change variety of chrysoberyl (beryllium aluminum oxide). This is a very rare and expensive gemstone. It has a hardness of 8.5, and its crystals are either tabular or prismatic. The distinction between alexandrite and chrysoberyl is simply color. A strange characteristic of alexandrite is that it is red, purple or violet when held under artificial light, but in daylight, it looks green.

July

Ruby is the standard birthstone for the month of July. It is a corundum (aluminum oxide) gem that gets its color from the presence of chromium in its structure. An exceptionally hard mineral, corundum illustrates a hardness of nine on the Mohs scale. “Pigeon-blood” red is the preferred color for rubies, though they also occur in lighter shades, including pink. All other colors of corundum are called sapphires.

Ruby exhibits all the desirable properties of a jewelry stone: beauty, durability, optical properties, and rarity. Some rubies display a star or asterism when fashioned into a cabochon. This effect is caused by the reflection of light from numerous inclusions of minute, needle-like crystals of rutile. Corundum crystallizes in the hexagonal system with a tabular-barrel-shaped habit.

August

Current birthstones for August are peridot, the gem-quality form of olivine and spinel. Olivine makes up a large portion of the earth’s mantle. Rocks containing olivine have been brought to the surface by volcanic action and actually blown out in the form of volcanic bombs. Masses of olivine have been found in meteorites, and the Apollo astronauts brought basaltic rocks back from the moon that contained olivine.

A popular jewelry stone, peridot has a hardness of 6.5-7 and can be transparent or translucent, with a vitreous luster. Its color shades from deep green to apple green, yellow-green or olive. It’s most often found in granular nodules, forming short, prismatic crystals in the orthorhombic system.

Spinel is the gem-quality member of the larger spinel group. Its hardness (Mohs 7.5-8.0) makes it ideal for jewelry use. Its spectrum of colors includes red, pink, purple, blue and lavender. In times past, red spinel was often mistaken for ruby. A notable example is the Black Prince’s Ruby, set in the royal crown of England.

September

The birthstone for September is sapphire. This term refers to any corundum (aluminum oxide) gem that has any color other than red (ruby). Sapphires may be colorless, blue, green, yellow, orange, brown, pink, purple, gray, black, or multicolor. At Mohs 9, its hardness is second only to that of a diamond.

Heat treatment is sometimes used to give natural blue sapphires a deeper, more pleasing color. Natural star sapphires, which display the optical phenomenon of asterism, are very rare.

October

Two options for October are opal and tourmaline. Opal is a magnificent gemstone with a play of color or “fire” in all colors of the spectrum. Spaces between the tiny spherules of silica that make up the gem diffract light into its spectral colors. Red, yellow, green and blue, in strong to pastel shades, flash from the stone when it is tilted.

Opal occurs in common and precious types. Common opal does not display any reflective fire. It may have a honey-yellow, brown, gray or colorless body color that is milky and opaque. Opal (Mohs 5-6) is not a very hard gemstone.

Tourmaline, a silicate of boron, has a complicated chemical composition, in which a number of elements, including calcium, iron, sodium and aluminum, may combine. It has a Mohs hardness of 7-7.5.

It belongs to the trigonal crystal system and its habit is hemimorphic (a crystal having two ends of an axes unlike in its planes).

Because of the coloration of the individual stones, tourmaline has several names, including schorl (black), rubellite (red), indicolite (blue), and dravite (brown). Tricolor crystals are common. The popular watermelon variety has an outer layer of green around a red core.

November

The current birthstones for November are topaz and citrine. People tend to think of topaz, a silicate mineral with aluminum and fluorine, as a yellow stone, but heat-treating and color-enhancing adaptations have made blue the predominant color on the market. It is an allochromatic mineral, which means its color is caused by internal defects in the crystal and has a Mohs hardness of eight.

Citrine is the golden member of the quartz family (silicon dioxide). Though quartz in its many forms is one of the most abundant minerals on earth, fine, gem-grade crystals are not that common. Citrine is affordable and, when faceted, rivals more expensive gemstones in beauty.

December

There are three birthstones for December: turquoise, blue zircon and tanzanite. Turquoise (hydrated copper aluminum phosphate) is an opaque, blue-to-green, massive gem material. It has a relatively low hardness of Mohs 5-6, so care must be taken with turquoise jewelry.

The rarest and most valuable variety is robin’s-egg blue with black “spiderweb” veins of limonite. Fake turquoise, consisting of dyed howlite or magnesite, is common. Buyer beware.

Zircon (zirconium silicate) can be blue, black, red, brown, green, yellow, smoky, or water-clear. It has an adamantine luster much like that of a diamond, and it is often misidentified as such.

Tanzanite, the blue/purple variety of zoisite (basic calcium aluminum silicate), is a recently introduced alternative for December. Tanzanite crystals in shades of yellow to brown, green, pink, gray or blue are often heat-treated to produce a gemstone that is a beautiful and permanent blue.

This story about what are birthstones by month previously appeared in Rock & Gem magazine. Click here to subscribe! Story by Kenneth H. Rohn.

The post What are the Birthstones by Month? first appeared on Rock & Gem Magazine.

Turquoise Facts

Real turquoise, not rocks dyed to look like turquoise, can be found in different parts of the world, but in North America, the desert Southwest provides the greatest source. The gemstone is formed only in arid climates when meteoric water originally from rain or melted snow percolates through voids in course copper-rich igneous rock. Turquoise results from the chemical reactions of the minerals that fill the void within the host rock, which is usually rhyolite, limestone, quartz, or chert. The color of turquoise produced is reflected by the amount of metal in the host stone. A higher incidence of copper produces a bluer turquoise, while more iron results in green coloration. High levels of zinc give the turquoise a yellower tone.

Turquoise has been mined in the U.S. for hundreds of years, with more than 400 turquoise mines in operation in Arizona, New Mexico, Nevada, Colorado, and California over the past two centuries. The first turquoise miners were the Pueblo peoples, who used stone mauls, axes, and chisels to remove it from its host rock. In 1908, turquoise became popular with tourists visiting the Southwest, and prospectors came to the area to mine it. The stone’s popularity soared to new highs in the late 1920s and early 1930s, resulting in the operation of more mines.

Colors of Life

While non-Native visitors to the Southwest were attracted to turquoise because of its bright color, the stone had—and still has— significant symbolic meaning to the Navajo, Zuni, Apache, O’odham, and other tribal nations. The color of turquoise is what sets it apart from all other stones in these Native cultures. “Turquoise was always appreciated by indigenous peoples as the blue ‘skystone’ and the green ‘mother earth,’” says Jacob “Joe Dan” Lowry, executive director of the Turquoise Museum in Albuquerque, N.M. “Other stones cannot match the colors of our created world.” Native people view turquoise as linked to the sky, water, and earth, making it representative of crucial elements of the natural world. The stone’s connection to water is especially strong, which gives it great significance in a land where water is both scarce and precious. For farming nations like the Navajo and Pueblo peoples, water was crucial for the survival of their crops and livestock.

Everyday Life & Ceremony

Given this symbolism, it’s not surprising that turquoise appears in both everyday Native life as well as in ceremonies. Turquoise jewelry is commonly worn at Native American cultural and civic events, and the Zuni use turquoise in prayer. In fact, for most Pueblo people, wearing turquoise is a way of asking for rain. For the Navajo, turquoise is closely linked to health, safety, and protection, and is also associated with the sun; the direction of the South; and Mount Tayler, a sacred mountain in New Mexico that plays a role in the Diné creation story. Turquoise is still used in Navajo ceremonies, including puberty rites, weddings, initiation, and healing. Navajo babies are given their first turquoise beads shortly after birth.

Turquoise & The Creation Myth

At the Acoma Pueblo in New Mexico, the oldest continuously inhabited community in the U.S., turquoise is an important stone. According to TSkies.com blogger Jeffrey Bacon, the creation myth of the Acoma reflects a widespread sentiment about turquoise in the Southwestern U.S. “According to the Acoma, the Creator, Iatiku, taught them to make turquoise and shell beads that had great power, making their wearer attractive and beloved,” said Bacon. The O’odham people of southern Arizona associated turquoise with strength and healing, while for other tribes, turquoise represented strength, skill, and even invincibility. “The Apache associated turquoise with rain at the end of the rainbow,” said Bacon. “They attached pieces to their bows to become precise and invincible hunters and warriors.” The Hopi considered turquoise to be the excrement of the lizard who travels between “the above” and “the below,” and Hopi miners carried turquoise to give them security and strength in their work, according to Bacon.

Wearing Turquoise

The Indigenous peoples of the American Southwest have become synonymous with turquoise and its use in various types of jewelry. For more than 1,000 years, jewelry adorned with this stone has been an integral part of the adornments worn by the peoples of this part of the U.S. Because of the significance of turquoise, it is often added in even a small way to jewelry made mostly from other stones. The tradition of using turquoise in bead necklaces, bracelets, earrings, and as inlays on shells continues today. Shells, once acquired through trade with coastal societies, are often paired with turquoise in jewelry because both are symbols of water.

Making Jewelry

Of all the Southwestern nations, Santo Domingo Pueblo artists are reported to produce the most traditional turquoise jewelry. Located 25 miles southwest of Santa Fe, New Mexico, the Santo Domingo Pueblo is home to around 2,500 tribal members and some of the most noted artists who work with turquoise. The Santo Domingo people have a long tradition of designing jewelry, and their creation story includes the making of jewelry. The Kewa, the people of this pueblo, are most famous for their hand-rolled heishi beads, many of which are made with turquoise. While turquoise jewelry has long been a part of traditional Southwestern culture, Native artists began making jewelry for sale to the non-native market at the turn of the 20th century. Tourists arriving in the Southwestern states were looking for souvenir jewelry to take home with them and were willing to pay well for it. The area became known for its turquoise and the beautiful jewelry that held it. In turn, turquoise became even more common within the Native cultures themselves.

“Turquoise has gained a greater appeal and allure since the 19th and 20th centuries, and into the 21st century,” says Lowry. “This greater appeal was due to outside cultures writing about turquoise and the Native American cultures in a variety of literature. Marketing and tourism played their part in growing the already established Native turquoise traditions, and finally, the 20th-century jewelry market and movie industry completed a forever love of turquoise through all generations of most Native culture.”

This story about turquoise previously appeared in Rock & Gem magazine. Click here to subscribe. Story by Audrey Pavia.

The post Turquoise in the American Southwest first appeared on Rock & Gem Magazine.

Stress Signs

Back-to-school can be stressful for everyone involved. For students, there are worries about the social pressures of fitting in, making friends, and getting good grades.

Some of the common signs of stress and anxiety in children and teens, as they return to the classroom, include physical ailments such as headaches and stomachaches. There are also a number of emotion-based challenges such as problems sleeping, changes in appetite, difficulty paying attention in class, irritability, anger, and bouts of unexplained crying.

Changes in Appetite

Some people want to eat more when they’re stressed and others feel just the opposite.

For those who tend to overeat to combat stress, an apophyllite pyramid on the desk or carried in a backpack or lunch box may help. If avoiding junk food is a challenge, an apatite stone can help to encourage healthy eating habits and is most effective when worn on or touching the skin.

Improving Concentration

Paying attention in class can be a struggle for students. For those in a distance learning program, the availability of distractions in online learning can make staying focused even more difficult. While there are many different colors of agates, each with its own metaphysical properties, all agates help to increase mental function, concentration, and analytical abilities.

Ametrine can improve concentration and help you to think things through thus building problem-solving abilities. It is most effective when worn for prolonged periods on or near the solar plexus.

Like agate, there are many different colors of apatite. All of the apatite varieties help to reduce aloofness and increase motivation.

Yellow apatite brings the added benefit of overcoming the inability to concentrate and improving learning efficiency. The end result can be that students are better able to concentrate and more excited and motivated to learn.

A piece of iron pyrite can help to improve blood flow to the brain making it easier to stay alert and overcome fatigue. Sodalite is an excellent stone for the mind. In addition to helping to reduce confusion, it encourages a feeling of trust and companionship among members of a group making the group work both more fun and productive.

Boosting the Immune System

For those who may be concerned about being in a group of people most of whom are strangers, an ametrine stone can provide support in several ways. It helps to strengthen the immune system and remove toxins from the body.

Iron pyrite boosts your immune system by helping to remove pollutants and infectious diseases. It is also reputed to alleviate asthma and benefit the lungs. This stone can be placed on a desk to energize the immediate area. It is also very effective when worn near the throat as jewelry or in a pouch.

Improving Sleep

Everything seems worse if you can’t get a good night’s sleep. Sodalite, muscovite, lapis lazuli, and hematite are four of the stones that can help to alleviate insomnia. Place a small stone under your pillow or a larger piece near your bed to improve sleep.

Green tourmaline also helps to promote a more restful sleep by improving patience and creating a sense of calm. Blue tourmaline can relieve congestion thus making it easier to get a good night’s sleep.

Reducing Stress and Anxiety

Holding onto worries is not good. A piece of cerussite may help people let go of the past.

Similarly, an apophyllite stone can have a calming effect and reduce stress by helping you release negative thought patterns.

Brown tourmaline helps a person feel more grounded as well as clears and protects both the aura and the etheric body. It fosters a feeling of community spirit helping students feel more comfortable and less anxious.

Providing Emotional Support

A blue lace agate in a pocket, backpack, or desk drawer can help a person feel more grounded and calm. It helps to keep emotions in balance. This stone’s ability to help people learn self-acceptance may be especially beneficial for those who feel insecure or uncertain in new environments.

Lapis lazuli stone can help to reduce the conflict that can arise when people are feeling out of sorts or irritable. It can also help alleviate depression and works best if worn between the sternum and the top of the head. Yellow apatite also works to reduce conflict by neutralizing stored-up anger.

Sodalite improves emotional balance and calms panic attacks. It helps to enhance self-esteem, self-acceptance, and self-confidence.

Selecting & Using the Stones

Pick up a stone, hold it, and see what you feel. Are you drawn to the stone? Does it speak to you? Many of the stones can be used alone or in conjunction with another.

If you feel drawn to more than one type of stone, try using them together. Let them support each other and you.

Alice, a junior high school student in South Dakota, finds the combination of amethyst and black tourmaline the perfect combination. “Amethyst for sure helps my anxiety a lot. I use black tourmaline for that too. I wear an amethyst pendant and the tourmaline is in my pocket or backpack.”

New Ways to Use Stones

Don’t hesitate to try new ways to use your stones. Alice uses a small quartz pendant for a zipper pull on her backpack.

Adam, a teacher in Portland in Oregon, used to let students borrow stones to use during class, something he can no longer do without cleaning and disinfecting the stones after each student. That became too difficult to manage so now he places stones around the room in strategic locations and rotates them as needed. “It doesn’t work as well as having the students hold the stones, but I still see a difference. If I know a student is really struggling or going through a particularly difficult time, I will sometimes quietly give them a stone they can keep.”

When asked how he knows which stone or stones will provide the most benefit, his answer was simple “I start with the intention of selecting the perfect stone. Then I go through the stones until I feel a pull toward one. That’s how I know it’s the one.”

It is important to remember there is no finite or definitive list of the metaphysical uses of rocks and crystals and nearly all of them can offer more than one type of support. It’s important to discover what works best for you.

Top 10 Stones for Back to School

In the case of distance or online learning, it’s possible to surround yourself with a multitude of stones. However, when you’re in a situation where you need to carry everything and can’t leave personal items behind, you may need to be more selective about what you bring. Choosing stones that can offer support in several needed areas can help lighten the load. The following is a list of 10 versatile stones and their properties.

1. Amethyst

A powerful stone with a high vibration that works to protect your energy. It acts like a natural tranquilizer helping to calm the mind, reducing anxiety and fears. It also helps you feel more focused and improves concentration.

2. Apophyllite

Known for helping to overcome anxiety, worries, and fears, apophyllite can help to reduce the craving for food. It has a calming effect, reduces stress, and releases negative thought patterns.

3. Ametrine

Helps to improve concentration and problem-solving by clearing stress and tension and calming the mind. It can enhance compatibility and acceptance of others. It can also help to remove toxins, improve the immune system and eliminate fatigue.

4. Black Tourmaline

Dispels negative energies and dissolves tension and stress.

It inspires a positive attitude and boosts the immune system. It is excellent for grounding, clearing the aura, breaking up negative energy, and balancing the chakra system. Encourages self-confidence, reduces fear, and invites compassion and tolerance. It can help release physical tension.

5. Blue Lace Agate

Excellent for grounding, and balancing the emotional, physical, and intellectual.

Soothes and calms a worried mind lowering emotional stress and stabilizing the aura. It helps boost self-confidence through self-acceptance. It can improve concentration, perception, and analytical abilities.

Helps to overcome anger and encourages you to start again. Aids the ability to neutralize infections and reduce inflammation.

6. Green Tourmaline

Encourages patience and a sense of belonging. Helps to quiet the mind and relieve insomnia and exhaustion.

Boosts the immune system and serves as a detoxifier. It is excellent for grounding, clearing the aura, breaking up negative energy, and balancing the chakra system. Encourages self-confidence, reduces fear, and invites compassion and tolerance. Helps release physical tension.

7. Lapis Lazuli

Harmonizes conflict, teaches the value of active listening, and helps to overcome depression. It benefits the respiratory and nervous systems, boosts the immune system, and alleviates insomnia. Wear at the throat, or anywhere between the sternum and the top of the head.

8. Sodalite

Encourages harmony, trust, and collaboration when working in groups. Calms the mind and helps to alleviate panic attacks. It can reduce mental confusion, and build self-esteem, self-acceptance, and trust in oneself. Helps boost the immune system.

9. Turquoise

It can help heal both the body and spirit and enhance the immune system. It aids in dispelling negative energy and protects against toxins in the environment. Helps to stabilize mood swings and bring inner calm. Can help alleviate exhaustion, depression, and panic attacks.

10. Yellow Apatite

Encourages healthy eating habits and helps to eliminate toxins from the body. It can increase motivation while overcoming emotional exhaustion. Helps to build energy reserves, and overcome a lack of concentration and inefficient learning. Releases frustration and neutralizes stored anger.

This story about the best crystals for back to school previously appeared in Rock & Gem magazine. Click here to subscribe. Story by Kris McElhinney.

Disclaimer: The metaphysical properties discussed in this story are not intended as a substitute for traditional medical treatment. If you have a health issue, please seek a licensed medical professional. The crystals and stones discussed are not intended to diagnose, treat or cure any conditions.

The post 10 Best Crystals for Back to School first appeared on Rock & Gem Magazine.

Turquoise is instantly recognized by its bright, waxy robin-egg blue shot through by dark veins. It is prized by collectors and jewelry makers but gets pricey. So how come sometimes it’s expensive and other times you can get a whole string of blue turquoise for cheap? What’s the secret to cheap beads? Often they’re not turquoise! Some common and inexpensive minerals can be dyed to look like rare and valuable stones.

Ancient Popularity

Turquoise is an iconic gemstone from the deserts of the Middle East and the American Southwest. It has been crafted into jewelry for thousands of years. How do we know this? Turquoise was discovered in the tomb of King Tut.

Turquoise Hacks & How to Make Turquoise

The turquoise look-alike hack? Dyeing inexpensive white rocks with veining similar blue. Minerals like howlite and magnesite are famous for how easy they are to transform into artificial turquoise. Howlite is usually soft and it has microscopic pores or open spaces to suck in blue dye. Here are six simple steps to make “turquoise” from howlite.

Step One

Get one or many specimens of howlite.

Step Two

Get a flat baking pan, kitchen tongs, a glass bowl or jar, Ty-D-Bol toilet cleaner or another dye such as blue food coloring or blue cloth dye. Experiment to see what dye works best. All these materials can be purchased at a 99- Cent Store for around $4.

Step Three

Prepare the howlite by placing it on a baking pan. Heat it in a kitchen oven at 200°F for at least 30 minutes. This opens pore spaces, making them larger than normal.

Step Four

Fill a jar with Ty-D-Bol or another dye. Using oven mitts, remove the baking pan from the oven. Using tongs, drop the hot howlite into the Ty-D-Bol liquid. Make sure the howlite is fully immersed and be careful not to splash the blue dye.

Step Five

Set the bowl or jar aside for several days or weeks. As the howlite cools, its pore spaces will contract. As they do so, they suck in the dye.

Step Six

Move to the kitchen sink with the bowl or jar. With tongs, pull out the pieces of howlite and rinse them under running water from the faucet, then place the specimens on a paper towel or cloth rag and allow them to dry. The result should look like turquoise.

Helpful Hints

Some specimens of howlite are softer and more porous than others. A harder specimen may not turn entirely blue. In fact, it may not suck in any dye at all! If this happens, try again with other howlite specimens. Crafting a cabochon with newly-made artificial turquoise may result in a white rock as it’s ground on a wheel. This is because the blue dye only penetrates the surface of the howlite. For an artificial turquoise cab, it’s best to first make it out of howlite and dunk it in Ty-D-Bol or another blue dye.

This story about how to make turquoise appeared in Rock & Gem magazine. Click here to subscribe. Story by Jim Brace-Thompson.

The post How to Make Turquoise first appeared on Rock & Gem Magazine.

Kingman turquoise has been a favorite of mine for many decades, and I have often used it in my goldwork. I believe the rich blue of Kingman should be accented with the rich yellow of gold. The first gemstone mine sales office I ever visited was to buy Kingman turquoise back in the late 1970s, and I still have some of the rough material from that purchase. With that, I was very pleased when Marty Colbaugh invited me to tour the Kingman mine itself.

I met Marty and his son Josh, first thing in the morning just outside of Kingman, Arizona at Colbaugh Processing, headquarters of the mine, and we hopped into their truck to head to the mine. It is a short drive from the main office to the mine, and during the drive, the two men talked about Kingman Mine history and their family’s involvement.

Kingman Character

Kingman Mine is in the Mineral Park area of the Cerbat Mountains in northwestern Arizona. This mountain range is primarily Precambrian gneiss, and many gold, silver and copper mines have operated there in recent history. The Kingman Mine is inside a copper mine. It is within two areas inside the copper mine, in Ithaca Peak and Turquoise Mountain. Currently, mining takes place on the face of Turquoise Mountain, as Ithaca Peak has been removed. There are many decades of reserves still to be mined, and the turquoise occurs in areas of sulfides and sulfide oxides. The upper sulfide oxide areas produce turquoise with more greens, and as you go deeper into the sulfide areas, the quality of the turquoise gets better and a richer blue.

Turquoise is present in veins, and as the veins go deeper into the ground, the quality of the material improves. Veins as thick as 40 feet have been found in this mine.

When Marty’s father, S.A.” Chuck” Colbaugh, first began mining Kingman, the diggings of Native Americans were still visible. At one time, he exposed a tunnel that had goatskin water bags and stone hammers still inside. The American Indians had been using turquoise from this mine for 1800 years or more, most often for personal adornment and trade purposes. Kingman turquoise traded through the ancient trade routes has been found as far as Mexico City. Archaeologists have been able to date the Mexico City area turquoise to 200 AD and have traced it back to this mine.

Chuck Colbaugh cut his first lapidary stone in 1929. He worked in the mining industry as a heavy equipment operator, welder and foreman in Battle Mountain, Nevada. Then he moved to Globe, Arizona, to work in the area mines. It’s believed the elder Colbaugh became the first person to stabilize Kingman turquoise after he put some chalky turquoise into epoxy. This discovery wouldn’t be his last. Colbaugh was an inventor and tinkerer and at one time held the patents on all the automatic cabochon cutting equipment in the US.

In 1962, Chuck Colbaugh heard that the Mineral Park Copper Mine was going to open, so he got permission to remove turquoise from the mine. Two years later, the Duval Mining Company began copper mining and Colbaugh retained his contract rights to mine turquoise within the mine. To this day, the Colbaugh family still has those contract rights, now with the Origin Mining Company of Canada. The copper mine is not currently in production but could restart any time Origin feels the market conditions were right.

Exploring Brilliant Blue Veins

Continuing with the tour, we drove up to the mine gate, and Marty punched in the security code to enter. After going through the gate, we switched to driving on the left side of the road. The drivers of the huge mining dump trucks have poor visibility to the sides, so for safety, all vehicles drive on the left side so the truck drivers can see other vehicles. While no large dump trucks are currently working in the mine since it is dormant, but the safety rules remain and are followed. After a short distance, we arrived at the large pit below the very tall mine face, but I was disappointed to see no actual excavation taking place. We were told someone had just headed to town for parts to repair vehicles, so they halted until they could get things running again.

Rather quickly, I could see blue veins of turquoise hundreds of feet up the face of the mine, but well below the top of the face. In order to mine the vein the crews cut benches, starting at the top of the face and work down. Each bench is 50 feet high and 25 feet wide, and the excavated rock is pushed off the bench and into the bottom of the mine pit until it is 150 feet deep. At this time, the rock is removed, ground, and graded into three sizes of rock. It then goes through the sorting shed.

There are two sorting sheds, and within each, two people were hard at work, pulling turquoise off conveyor belts. If they have hit a particularly rich area of material, the rock is recirculated through the belts to make sure nothing is missed. The sheds are small and air-conditioned.

The group is very strict on safety and have never lost an hour over an accident. They routinely get top ratings for safety from the Mining Safety and Health Administration (MSHA) and recently received a “0” citation report after an inspection. A no citation report is so unusual that MSHA sent another inspector out to confirm, and he also turned in a “0” citation report.

All-In-One Operation

As we returned to the mine headquarter, I toured the manufacturing facility. The

company does all of the manufacturing of the products they sell. They used to have all of their stone cutting done in China, but eight years ago, they decided they could do it cheaper themselves and have had great success in doing so. Today the company employs nearly 50 people, with crews working in the mine, the manufacturing facility, and in the office and salesroom.

Carrying on the stabilization tradition set forth by Chuck Colbaugh, a great majority (95 percent) of the rough material removed from the mine is stabilized or pressed into bricks. This material is too soft or too small to be formed into cabochons or beads, but nothing goes to waste, and Colbaugh Processing is among the leaders in the stabilization of turquoise, using a stabilization process with optically clear resin under no pressure. The stones weigh the same after stabilization as before. In a recent development, Rolex is manufacturing a Kingman turquoise dial watch, and the company only wanted stabilized material for the consistency and lack of color change.

A small percentage of their mined material is unusable even for stabilizing. New technology has created colorful pressed bricks ready to be cut into gems with a bronze spider webbing. Marty Colbaugh bought this process and perfected it into a product that cuts into beautiful, consistent stones. The pressed bricks come in many colors, some dyed, and others with turquoise mixed with other stones such as malachite, azurite, Spiny Oyster shell and pink opal. The company’s Mojave Green bricks got their name when a Mojave Green rattlesnake wandered into the shop. However, I don’t think the actual snake is in any of the bricks.

A unique combination of brick is the blue and orange version created by mixing turquoise with orange-colored Spiny oyster shells. These shells are a byproduct of Mexico’s shell food industry, which means no oysters had to die for the production of the jewelry. Josh Colbaugh suggested the brick combination to his father since Native American silversmiths used the Spiny Oyster shells in combination with turquoise. Marty felt otherwise but was wise enough to let Josh experiment with this notion, and now it is their best seller. I think this combination looks great, and I bought some bead strands.

Whether the stones are natural, treated or made into bricks, they go into the cutting shop to become cabochons, beads, cell phone case accessories, and candle holders, among other items. With this process, the company uses mass-production techniques to preform, then hand cut and polish. They make cabs using a preform cabochon cutter from Germany, not the one that Chuck Colbaugh invented. It turns out the efficiency of the German machine is more important than nostalgia in this modern workshop.

Intrigued By Equipment and Creativity

I was fascinated by the bead cutting equipment as I had never seen how beads were made. But, my favorite machine was the dopper. It uses hot glue heated with natural gas to dop up to 26 cabs at once. They are perfectly centered and are ready to go into the automatic preform machine. After preforming is done, workers at banks of cabbing machines put an excellent polish on a wide variety of calibrated shapes and sizes, and then the stones are ready to go to the salesroom.

The salesroom is new and an improvement from the previous space. It is big, provides a lot of room to wander around and look at the bead strands, rough material, trays full of calibrated cabs, cases full of finished jewelry, and the bricks manufactured in the shop. My favorite part of the sales area is the rough material room just off the main floor. This room contains bins full of treated and natural rough material in various sizes and qualities. I picked out some slabs that are natural veins 4” x 4” and 1/3” thick, plenty big enough to cut a nice belt buckle cab.

The Kingman that I drool over most is the spiderweb, and there is plenty to choose from in both stabilized and natural. There is spiderwebbing in various colors such as blue and black or white, but I am fond of black spiderwebbing. I have cut stones from it and have found the webbing to be consistent as I cut through stone. I was pleased to find some blue webbing just like the first pieces of Kingman I bought 40 years ago. It has dark blue webbing with a light blue interior, very beautiful.

Colbaugh Processing is a family operation with the third and fourth generations of the Colbaugh family involved with the company. Hopefully, the fourth generation will keep this family business moving forward, and with the known reserves of the mine, they will continue to have turquoise to mine and cut and sell.

The mine office is just seven miles north of Kingman, Arizona. If you find yourself in the area and are a lover of turquoise, you need to stop in. There is enough for everyone to drool over, trust me. For more information, visit www.colbaugh.net.

The post Spending Time At Kingman Mine first appeared on Rock & Gem Magazine.

One of the gifts that ruler Moctezuma II lavished upon Spanish conquistador Hernán Cortés when he arrived in the Aztec Empire in 1519 was a chest ornament depicting a double-headed serpent. Displayed today in the British Museum in London, this 20-inch-long, 8-inch-high ornament, inlaid with white shell, red coral, and thousands of blue turquoise pieces is among the most extraordinary pre-Columbian artifacts to survive the Spanish conquest of what is now Mexico.

Turquoise held a special place in the Aztec value system. Its rarity alone made it precious; even more importantly, its blue-green color signified the land’s fertility, one of the Aztec culture’s major precepts. Also symbolizing water, new growth, and the revered quetzal bird’s feathers, turquoise was sacred to the Aztecs and the contemporary Mixtec culture and the Mayans who preceded them.

The colorful mineral is prominent among the artifact materials of the Aztec, Mixtec, Zapotec, Tarascan, and Mayan pre-Columbian cultures of Mesoamerica (a region stretching from southern Mexico to Honduras), and archaeologists have long debated its source. However, most have agreed that Mesoamerican turquoise was actually mined 1,200 miles to the north in what is now the American Southwest, then brought to Mesoamerica via an extensive trade system that operated for centuries.

The evidence supporting this theory, while circumstantial, is nevertheless convincing. First, Mesoamerica has no documented turquoise deposits, while the Southwest has many. Second, the peak Mesoamerican use of turquoise coincides closely with the height of pre-Columbian turquoise mining in the Southwest. And finally, the recovery of copper bells, cacao, scarlet macaw feathers, and other Mesoamerican trading commodities from southwestern cultural sites indicates the existence of some level of commerce between Mesoamerica and the Southwest.

Nevertheless, without scientific proof, the existence of this turquoise-trading system was just a theory that could be proved—or disproved—only when chemical testing positively linked turquoise specimens to their deposits of origin. Initially, establishing the provenance of turquoise or, as geochemists now say, “fingerprinting,” turquoise, seemed a simple matter of basic chemistry that called for identifying a chemical characteristic of turquoise unique to each mine source. But as it turned out, fingerprinting turquoise would be a complex process developed only after a century of trial-and-error experimentation.

But the early effort has now paid off. By measuring the isotopic ratios of trace elements in turquoise specimens and comparing them with the proportions in databases representing the host rock of turquoise deposits, researchers are now beginning to trace turquoise specimens to their source reliably.

Emergence of Turquoise-Related Subscience

Although this subscience is still in its developmental stages, initial results have already raised eyebrows among archaeologists and anthropologists by refuting two long-prevailing theories: First, that Mesoamerican turquoise came from the American Southwest and, second, that New Mexico’s Chaco Canyon culture, the greatest of all pre-Columbian turquoise-working societies, obtained all its turquoise from the nearby Cerrillos mines. As a result, scholars are now rethinking the entire picture of the pre-Columbian turquoise trade.

Turquoise is a basic copper aluminum phosphate with the chemical formula CuAl6(PO4)4(OH)8·4H2O. Ideally, its weight consists of 7.81 percent copper, 19.90 percent aluminum, 15.23 percent phosphorus, 55.08 percent oxygen, and 1.98 percent hydrogen. Turquoise is one of the 300-plus members of the phosphates, arsenates, and vanadates class of minerals.

Crystallization occurs in the triclinic system, which has three axes of different lengths, none

perpendicular to the others. Because this low-symmetry arrangement inhibits crystal development, turquoise macro crystals are rare, small, and poorly formed. Most turquoise consists of tightly bonded microcrystals in massive or compact forms. The close atomic packing creates strong atomic bonding and a substantial hardness of Mohs 5.0-6.0.

Turquoise is one of five members of the turquoise group of closely related triclinic phosphates, which includes chalcosiderite [basic copper iron phosphate, CuFe6(PO4)4(OH)8·4H2O]. Turquoise and chalcosiderite form a solid solution series in which ferric iron (Fe3+) replaces aluminum (Al3+) and vice versa. When close to its ideal composition, turquoise is a “robin’s-egg blue” color; increasing amounts of iron impart a pronounced greenish shift.

As a secondary mineral, turquoise occurs in shallow oxidation zones of copper-rich deposits. The copper in turquoise is derived from the alteration of copper-sulfide minerals, aluminum from the alteration of feldspar and clay minerals, and phosphate radicals from groundwater-dissolved fluorapatite [calcium fluorophosphate, Ca5(PO4)3F]. Turquoise forms in low temperatures and pressures, as well mainly in warm, arid climates. Hydrothermal deposition typically creates thin veins, fracture coatings, and nodules.

Ancient Appreciation and Application

The reverence for and appreciation of turquoise in the Americas originated in Mesoamerica. Archaeologists have contextually dated the earliest known Mesoamerican turquoise artifacts to 650 BCE at the beginning of the Mayan Preclassic Period. The use of turquoise in Mesoamerica remained limited until about 1000 CE in the Mayan Postclassic Period, after which it began to appear more frequently in masks, jewelry, and mosaic inlays.
Turquoise had its most significant importance among the Aztecs. After 1430 CE, during the Aztec Late Postclassical Period, turquoise was used in the shields and hilts of sacrificial obsidian knives and personal ornamentation and masks. The most prominent use was in elaborate mosaics that were inlaid with thousands of small turquoise tiles.

In the American Southwest, turquoise mining did not begin until around 200 BCE—450 years after the Mayans first mined it in Mesoamerica. Anthropologists conclude that turquoise’s ritualistic and economic uses evolved in Mesoamerica and spread northward to reach the Southwest eventually. Southwestern turquoise production increased rapidly after 850 CE, when Ancestral Puebloans began large-scale, systematic mining at Cerrillos, just south of present-day Santa Fe, New Mexico. Simultaneously, 100 miles northwest of Cerrillos, the Chaco Canyon culture was entering a period of rapid expansion and development. By 950 CE, Chaco Canyon had become the Southwest’sSouthwest’s leading source of worked turquoise and the hub of a high-volume turquoise trade.

Chaco Canyon was abandoned around 1150 CE, almost at the same time that large-scale turquoise mining ended at Cerrillos. Chaco Canyon’s abandonment has been variously attributed to the closure of the Cerrillos mines, economic failure due to competition with other southwestern turquoise sources, or the effects of a prolonged drought—or perhaps a combination of all these factors.

Records and artifacts revealed the modern history of southwestern turquoise dates to the 1880s when Anglo Americans began commercial mining. During this same period, members of such Native American groups as the Navajo, Hopi, and Pueblos began setting turquoise in silver (the latter obtained by melting down U.S. silver dollars) and selling this jewelry to travelers on the newly built railroads.

By 1910, the image and future of turquoise marketing in the United States had been firmly established: As the Southwest’s iconic gemstone, turquoise would subsequently be set in silver mounts of “Indian” and “southwestern” designs, and color enhancement of using blue aniline dyes, would become common.

As the popularity of turquoise soared, provenance became an issue. Turquoise from such classic sources as Cerrillos had considerably greater consumer appeal and brought higher prices than generic stones or stones from lesser-known sources. But because turquoise origin could not be proven, it was often misstated for marketing purposes. The hope was that scientists soon would develop a method to determine turquoise provenance positively. Archaeologists were also interested in determining the origins of turquoise mainly to prove their new ideas regarding pre-Columbian turquoise trading patterns, the growing belief that large quantities of southwestern turquoise had ended up in Mesoamerica.

Process of Confirming Provenance

The first efforts to determine turquoise’s provenance were based on visual appearance, specifically color, type of veining, and nature of the matrix, along with general assessments of hardness and workability. The chances of visually determining origin were best with natural matrix specimens. They were much poorer with worked turquoise because cutting and polishing eliminated certain natural characteristics—a particular concern to archaeologists. Because most turquoise artifacts recovered from cultural sites had been worked into beads and tiny inlay pieces, attempts to establish provenance were largely guesswork initially.

Chemists first tried to determine turquoise provenance with simple quantitative tests and qualitative spectrographic analyses. But problems quickly arose due to turquoise’s inherent chemical complexity. Because turquoise deposits often form through multiple-phase hydrothermal emplacement, wide compositional variations in both primary and trace elements, even among specimens from the same deposit, made single-element analyses ineffective.

Researchers eventually realized that the key would be to identify a specific, measurable chemical signature constant in both turquoise specimens and their original mineralogical environment, yet sufficiently unique to differentiate individual specimens and their deposits of origin. But finding this signature would be akin to seeking the proverbial needle in a haystack.

By the 1990s, researchers had tried X-ray fluorescence, arc-emission spectrometry, neutron-activation, and electron-microprobe methods, along with comprehensive computer analyses of the mathematical values of turquoise’s basic and trace elements. While the results were sometimes encouraging, overlapping data prevented identifying chemical signatures that were unique for individual turquoise deposits.

In 2004, researchers turned their attention to elemental isotopes. Isotopes are atoms of the same element with the same general chemical properties of the parent element, but with different numbers of neutrons and a different atomic mass. Geochemists first measured traces of the isotopic lead that are always present in turquoise, only to find that single-isotope data, like single-element data, could not differentiate individual deposits.

Next, they measured the ratios between two elemental isotopes, working first with hydrogen-oxygen ratios, then moving on to copper-hydrogen ratios to achieve their first success. In 2010, using the copper-hydrogen approach, they conducted 800 analyses of turquoise specimens from 22 southwestern deposits. They correctly sourced 42 of 74 turquoise artifacts recovered from cultural sites in Utah and Nevada after building a database. The inability to source all the specimens was mainly because the chemical signatures of all southwestern turquoise deposits had not yet been entered into a database.

Research with turquoise specimens from New Mexico’s Chaco Canyon is particularly interesting. Chaco Canyon, now protected as Chaco Culture National Historical Park and designated a United Nations Educational, Scientific and Cultural Organization World Heritage Site, has yielded a quarter-million pieces of turquoise, the most of any site in the world. This turquoise consists mostly of drilled beads, pendants, and mosaic-inlay pieces.
Within the greater Chaco Canyon cultural region are the ruins of several “great houses,” large, multistory Ancestral Puebloan structures, each of which was a semi-independent community of turquoise workers. Analyses of specimens from these sites showed that only the Pueblo Bonito great house worked with Cerrillos turquoise. This information was the first major revelation about the Southwest’sSouthwest’s pre-Columbian turquoise trade. Turquoise specimens from Chaco Canyon’sCanyon’s other great houses had come from mines in California, Nevada, and Colorado.

Archeologists now believe that Pueblo Bonito had monopolized the Cerrillos mine supply while the other great houses obtained their turquoise through trade with groups far to the west. Apparently, this was often a two-way trade, as Cerrillos turquoise has been found at sites in California, Utah, and Nevada. By the time these revelations were announced, researchers were already developing an even more reliable technique that measured the isotopic ratios of lead and strontium in turquoise. In 2012, researchers used this method to analyze 150 specimens to compile a database of dozens of turquoise deposits in California, Arizona, New Mexico, and Colorado, all of which showed evidence of pre-Columbian mining.

Next, they analyzed two groups of pre-Columbian turquoise mosaic tiles. One had been excavated from the Templo Mayor, the Aztec Empire’s ceremonial and ritual center, in present-day Mexico City. The second group, from the Smithsonian’s National Museum of the American Indian, consisted of artifacts of the Mixtec culture, an advanced civilization in western Mexico that paid tribute to the Aztecs.

Isotopic signatures of the turquoise in both groups were consistent not with the geology of the Southwest, but with that of Mesoamerican crustal rocks and native-copper deposits. This signature result was the first clear evidence that Mesoamerican turquoise did not come from the American Southwest. It also raised the obvious question: Where did the Mesoamerican turquoise originate?

Although no Mesoamerican turquoise sources have yet been documented, 19th-century ethnohistorical and archaeological literature includes second-hand reports of turquoise deposits in Jalisco’s Mexican states Puebla west and south, respectively, of Mexico City. These regions have numerous, albeit small native-copper deposits mined in pre-Columbian times to obtain metal for tools, bells, and ax heads. Archaeologists have also found evidence of crude, pre-Columbian copper smelters that treated locally-mined, oxidized copper ores.

Turquoise could undoubtedly have been present in these native-copper and oxidized-copper

deposits. And because turquoise occurrences are always small and shallow, they also could easily have been mined out, destroyed by native-copper or oxidized-copper-mineral mining, or lost and overgrown in the long period of societal collapse that followed the Spanish conquest.

The lead-strontium test results indicate only that Mesoamerican turquoise did not come from the American Southwest. The lead-strontium ratios are consistent with the surface geology of Mesoamerica. But in the absence of known turquoise sources, this data does not yet link the Mesoamerican turquoise to any specific regional sources. But archaeologists are already looking closely at the known Mesoamerican native-copper deposits. Should turquoise be found here, lead-strontium tests will reveal if these particular deposits were among the turquoise sources in pre-Columbian artifacts.

While the lead-strontium turquoise-fingerprinting technique offers excellent promise to gain insight into pre-Columbian turquoise-use patterns, a database must first be compiled of all known southwestern turquoise sources. However, the lead-strontium analytical process itself is neither quick nor simple. As one researcher points out, it is not “something that can be done in the garage.”

Specimens must first be identified as turquoise and not another similarly colored, oxidized copper mineral, such as malachite or chrysocolla, each of which often masquerades as artifact turquoise. The chemical composition must be confirmed with such nondestructive techniques as X-ray-diffraction and scanning-electron microscopy. Specimens must then be cleaned of all residue or adhesive material, crushed to a powder, cleaned again, dissolved in acid, precipitated, dried, then prepared for specific tests. Only after this test material is degassed on titanium filaments can thermal-ionization mass spectrometers measure strontium-isotope levels and plasma-mass spectrometers measure lead-isotope levels.

Although lead-strontium isotopic analysis requires only tiny specimens, it is nevertheless a destructive process that is not suitable for all museum artifacts. Isotopic analysis may soon be used to determine the provenance of the turquoise in Egyptian artifacts. The turquoise used as early as 3200 BCE in Early Dynastic Egypt was probably obtained from deposits in the nearby Sinai Desert. But after 1000 BCE, the nature of the turquoise in Egyptian artifacts seems to have changed. Some Egyptologists suggest that the Sinai mines had been depleted and that the new turquoise was coming from Persia (now Iran), 1,500 miles to the northeast—a theory that could be confirmed by lead-strontium isotope analysis.

Although still in its formative stages, the specialized subscience of turquoise fingerprinting has already provided fascinating new insight into pre-Columbian cultural and economic relationships, the scope of ancient trade routes, and the origin of Mesoamerican turquoise. And when advanced, nondestructive, and economical isotope-ratio techniques become available in the not-so-distant future, we may finally know if our prized specimens of Cerrillos turquoise are really from Cerrillos.

The post Fingerprinting Turquoise first appeared on Rock & Gem Magazine.

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In addition, you’ll find the following regular R&G columns: Bench Tips with Bob Rush, Rock Science with Steve Voynick, What to Cut with Russ Kaniuth, On the Rocks with Bob Jones, Rock & Gem Kids and Earth Science In the News with Jim Brace-Thompson, Sneak Peek: Opals, The Road Report with Helen Serras-Herman, Picks & Pans, Show Dates, and the always popular Parting Shot.

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Native Americans once “owned” all the turquoise deposits in what is now the United States, not in terms of today’s legal definition of ownership, but by virtue of discovering the deposits and having been first to mine, work, and trade the turquoise. But after Europeans arrived, the turquoise mines became and remain, for the most part, Anglo property.

The exception is the North Star Mine in Cripple Creek, Colorado. The North Star is owned by Clint Cross, a registered member of the Sokoki Tribe of the Abenaki Nation of Missisquoi, along with his wife Louisa McKay and Australian partners Graham and Anna Slater. Clint is the only Native American to currently own and operate an active turquoise mine.

North Star Mine turquoise is distinguished both by the mine’s Native American ownership and its superb, natural gem qualities of saturated blue-green colors, distinctive matrix patterns, and extraordinary hardness.

Expanding on a Turquoise Tradition

Although new on the market, North Star turquoise already has a heritage as the latest chapter in the story of Cripple Creek turquoise. Cripple Creek, of course, is first and foremost synonymous with gold. Perched 9,500 feet high on the western slope of Colorado’s iconic Pikes Peak, the town is named for a nearby rocky creek notorious for crippling cattle. Cripple Creek was born in an 1892 gold strike; just eight years later it had grown into a booming city of 20,000 residents with 400 mines turning out one million troy ounces of gold per year.

The first miners at what is now Cripple Creek, however, were not gold miners, but Native Americans who collected turquoise from exposed veins. Their points and scrapers of flaked chalcedony are found today along with bits of turquoise on the surface of the North Star Mine.

“Turquoise was not mined in Vermont where I was born and raised,” Clint admits. “But my people—the Abenaki—recognized its spiritual significance and passed that along to me. So owning a turquoise mine today means a great deal to me—it’s something I feel I was meant to do.”

Turquoise has long held a special place in the beliefs of Native Americans, especially those cultures indigenous to the turquoise-rich Southwest. While Native Americans admired turquoise for its beauty, they also venerated it for its spiritual, religious, and ritualistic significance.

Cultural Connections

Some cultures considered turquoise a part of the sky that had fallen to Earth; its blue-green colors symbolized the connection of Earth with sky, and body with spirit. In Navajo and Hopi creation legends, turquoise represents sky, water, bountiful harvests, health, and protection.

It is also an element in Zuni rituals and Navajo rain ceremonies. Apaches linked turquoise to rain at the end of rainbow and attached bits of the stone to their bows in the belief that it guided their arrows.

Cultures far beyond the Southwest also recognized turquoise’s sanctity. Turquoise mined in the Southwest has been recovered from indigenous cultural sites as distant as Florida, Canada, Central America, and the Caribbean.

The Southwest has more than 200 significant turquoise sources, most related to shallow, oxidized copper deposits in New Mexico, Arizona, and Nevada. Top-quality turquoise, however, is rare. Fewer than a dozen sources consistently yielded turquoise in which color, durability, and hardness did not require artificial enhancement. Most of these sources have been mined out and others lost to open-pit copper mining.

Turquoise Deposits in Colorado

As a relatively minor source of turquoise, Colorado has just five

significant deposits, all in the south-central part of the state. Among them are Turquoise Chief Mine in Lake County, the Last Chance Mine at Creede in Mineral County, the King Turquoise Mine in Manassa, Conejos County, Villa Grove in Saguache County, and Cripple Creek in Teller County. The North Star Mine at Cripple Creek is now Colorado’s only active turquoise source.

Colorado turquoise occurs in a variety of mineralogical environments. At the Turquoise Chief, it is present as veinlets in granite; at the Last Chance, it is found in heavily oxidized sections of the silver-rich Amethyst Vein. Villa Grove turquoise occurs as veinlets in altered gabbro. At Manassa, Native Americans originally mined turquoise from underground workings in solid basalt, and the site was later mined commercially. At Cripple Creek, turquoise veins are found in altered diorite.

Turquoise (CuAl6)(PO4)4(OH)8·4H2O) is hydrous copper aluminum phosphate, a secondary mineral that forms under specific hydrological and mineralogical conditions from the weathering of rocks rich in aluminum, copper, and phosphate minerals.

The Cripple Creek deposit is located within the Central Colorado volcanic field, an extensive area of volcanism that dates the early Oligocene Epoch some 34 million years ago. All local mineralization is related to the Cripple Creek caldera, a collapsed volcanic system created when eruptions alleviated magmatic pressure, causing a volcanic dome to subside and fracture.

Exploring Ores

Mineral-rich, hydrothermal solutions associated with repetitive surges of magma then emplaced metallic gold and the gold-telluride minerals calaverite and sylvanite. The Cripple Creek caldera is a circular mass of brecciated rock five miles in diameter. Gold and gold-telluride minerals occur within its core in rich veins and pockets. Surrounding this core is a much larger area of disseminated, low-grade gold mineralization. The high-grade core fueled Cripple Creek’s mining boom of the 1890s; today, a modern, open-pit mining operation exploits the low-grade ores.

Copper mineralization occurs only in a small area at the caldera’s northwestern edge, where it was emplaced by hydrothermal solutions that circulated though a fault in the diorite host rock. This north-south-oriented fault controlled the emplacement of all Cripple Creek turquoise. Interestingly, bits of native gold are occasionally seen within the turquoise itself.

When gold was discovered at Cripple Creek in 1892, an abundance of turquoise lay scattered about the surface. But most miners were concerned only with gold; only a few collected turquoise, usually as a novelty item to trade for drinks in the local saloons.

Musician and part-time gold prospector Wallace C. Burtis was first to take a serious interest in Cripple Creek turquoise. In 1939, he bought a claim, not for its poor showing of gold, but for the turquoise that lay on the surface. Burtis renamed the claim the Florence Lode, taught himself gem cutting, silversmithing, and jewelry making, and began mining, working, and selling turquoise. He passed these interests and skills on to his son Wallace F. (Wally) Burtis who continued mining and later sold stones under the name “Burtis Blue Turquoise.”

Celebrating Heritage Through Mining

By 2010, Wally and his wife Joanne, getting on in years and needing help with mining and marketing, hired Clint Cross and Louisa McKay. Both already experienced with Cripple Creek turquoise, Clint and Louisa took over mining operations at the Florence Mine and marketed Burtis Blue Turquoise at gem-and-mineral shows.

Clint took an indirect route to Colorado from his Abenaki birthplace in northern Vermont. The Abenaki—the name means “People of the Dawn”—are an Algonquin-speaking culture that once populated present-day Vermont, New Hampshire, Maine, and adjacent sections of Canada.

Today, 6,000 Abenakis, mostly in Vermont, maintain tribal unity to preserve their language, customs, and traditions. Lacking federal recognition as a tribe, however, they have no reservation. But because Vermont recognizes the Abenaki, they qualify for educational funds and use of the designation “native made” on their arts and crafts.

As a boy, Clint took pride in his heritage and learned the traditional Abenaki skills of hunting, fishing, trapping, and wilderness survival. He later ran a construction outfit in Florida, then a trail-riding business in Louisiana. Moving to Colorado in 1998, he did some prospecting, which led him into turquoise mining in Cripple Creek. He and Louisa, who is also interested in mineral collecting and the outdoors, married in 2008.

Building a Future Through Turquoise Mining

In 2017, when Wally and Joanne Burtis became uncertain about the future of their Florence Mine, Clint and Louisa began considering their own future in turquoise mining.

“We were always interested in the property north of the Florence Mine,” Clint says. “The geology indicated that the turquoise veins extended onto that property. Although it had never been mined, Louisa and I had found turquoise right on the surface. When we learned that the property was available, we saw a chance to own a turquoise mine.”

Clint and Louisa acquired the property in August 2017, named it the North Star Mine, and began mechanical exploration into the soft, weathered diorite. They soon exposed a heavily altered seam—a section of the fault that had controlled local turquoise emplacement. Further excavation revealed erratic veins and pockets of turquoise within the crumbly, hematite-stained, yellowish-brown diorite.

Thanks to his previous construction experience, Clint performs the mechanical excavation himself, which halts at the first sign of turquoise veins. These appear in the host rock as unremarkable, dark trends that would escape the attention of an inexperienced eye. But closer inspection and a bit of rock-pick work quickly reveals the bright, blue-green colors of North Star turquoise. While the veins themselves are thick enough to provide gem turquoise, they sometimes “blossom” into pockets that can yield solid turquoise an inch or two thick and several pounds in weight.

Shades of Pure Turquoise

Almost all turquoise mined in the world today is not of gem quality. It

lacks the color intensity to appeal to gem and jewelry buyers, the structural integrity to withstand cutting stresses, and the hardness necessary to polish nicely and endure jewelry wear. Turquoise is abundant on today’s jewelry market today because most of it is inferior material that has been treated to improve color, structure, or hardness.

Pure turquoise has a bright, clean, “robin’s-egg”-blue color. But varying quantities of iron and other metals that substitute for copper within its crystal lattice often shift this basic blue color toward green.

The colors of North Star turquoise range from blue and greenish-blue to bluish-green and green, and occasionally even to a delicate purple. This broad color variation indicates multiple-phase emplacement in which each depositional phase varied in chemistry.

Turquoise hardness generally ranges from Mohs 5.0 to 6.0, depending upon degree of silicification and, to a lesser extent, the nature of accessory-metal substitution.

Silicification occurs when silica-rich solutions deposit microcrystalline quartz within the turquoise pores to fix and intensify color, seal pores, and substantially increase hardness.

Testing Turquoise

Well-silicified turquoise resists both abrasion and discoloration from the absorption of skin oils. North Star Turquoise, which is unusually well-silicified and contains traces of corundum (aluminum oxide, Mohs hardness 9.0), actually attains a Mohs hardness of 6.5 or higher.

North Star turquoise is completely natural and has the documentation to back it up. Stone Group Laboratories, a leading gem-testing laboratory, has subjected it to X-ray-fluorescence, raman, fourier-transform-infrared, and ultraviolet-visible-near-infra-red-spectroscopy analyses. By revealing chemical composition, molecular structure, and bonding characteristics, these tests can detect the presence of plant dyes, epoxy stabilizers, and potassium compounds that are the “fingerprints” of turquoise treatment.

All North Star turquoise is accompanied by a Stone Group Laboratories statement attesting to the fact that it is untreated. Clint and Louisa also maintain direct control over all aspects, from mining to marketing.

Matrix is another distinctive feature of North Star turquoise. Matrix—the visible, non-turquoise mineralogical materials within the turquoise—enhances the overall appearance of turquoise gems by accenting and adding interesting patterns to the basic blue-green colors. Much North Star turquoise has a particularly attractive matrix of golden-brown veins and thin, black hairlines. The golden-browns are limonite, a variable mixture of iron hydroxides and oxides; the black hairlines are pyrolusite, or manganese oxide.

Turquoise Tumblers

This sharply defined, intensely colored matrix results from unusually high heat levels that accompanied the hydrothermal-deposition process. One especially attractive matrix type consists of oxidized-iron compounds that reflect light in the manner of bright, burnished copper.

After mining, North Star turquoise is tumbled to remove adhering bits of the yellowish-brown host rock. Clint’s “tumblers” are two rotary cement mixers, each of which he loads with water and 150 pounds of rough turquoise. The turquoise is first tumbled for two 12-hour periods and screened after each run, then put through a final three-day tumble. The tumbling medium is turquoise bits that are too small for inlay or jewelry use.

Clint and Louisa then sort the tumbled turquoise by size and shape. Turquoise to be retained in its natural shape is sandblasted with 80-grit garnet at a pressure of 165 pounds per square inch to smooth the surface and remove any undesirable features. Stones destined for cutting are shaped on a 10-wheel lapidary unit with increments from an 80-grit rough-shaping wheel to a 14,000-grit fine-polishing wheel.

Clint and Louisa, together with Katy Pickens, a silversmith from nearby Breckenridge, Colorado, make their own jewelry.

“Personally, I don’t copy existing jewelry styles or traditions,” Clint says. “My Abenaki name is ‘Stand Alone,’ which describes my preferences in turquoise jewelry. Rather than adhering to existing styles and traditions, I consider each stone to be unique in color, size, shape, matrix, and spirit. The spirit of each stone tells me how it should be used in jewelry.”

Fault Line Exploration

Preliminary exploration along the fault line and its associated turquoise-vein systems indicate that turquoise reserves at the North Star Mine are sufficient for decades of mining. Looking toward the future, Clint has already assured that the North Star Mine will always remain in Native American hands. Should something happen to Clint, and neither Louisa nor son Clevalden wish to continue mining, the property will go to the Abenaki Nation in perpetuity.

When I last visited Clint and Louisa at the North Star Mine in November of 2018, they had mechanically exposed a new fault section in the morning, then collected 15 pounds of rough turquoise in the afternoon. Before wrapping up the day’s work, they made another find—a one-inch piece of turquoise lying alongside a flaked chalcedony arrowhead.

“That point reminded me that my ancestors once gathered turquoise from this same deposit,” Clint said with a smile, “and I think they’d be pleased that I’m here today.”

Clint and Louisa are regular vendors at national gem-and-mineral shows in Tucson, Houston, and Denver, and also at Colorado regional shows in Colorado Springs, Creede, Buena Vista, Woodland Park, and Fairplay.

For further information visit www.northstarturquoise.com or contact Clint Cross and Louisa McKay at (802)782-7330 or crossfamily1000@aol.com.

The post North Star Turquoise first appeared on Rock & Gem Magazine.

• North Star Turquoise: New, Natural and Native American. By Steve Voynick

• Black Smoker Geysers: Loaded with Sulfide Minerals, They’re A Miner’s Best Friend. By Bob Jones

• In Memoriam: Carolyn Weinberger. By Bob Jones and Jim Brace-Thompson

• Special Section: Tools of the Trade

• Carrying On Cutting Traditions: Roth Family Favors Cameo Carving. By Bruce McKay

• Tucson 2019 Recap: An Experience of Change and Growth. By Bob Jones

• Emerald Village: Mines and Museum in Little Switzerland. By Helen Serras-Herman

• Understanding Orb Structure in Jaspers: Manifestations of Enigmatic Phenomenon (Part I). By Joe Dehmer

• Enchanted By Selenite: Unexpected Discovery Makes Dreams Possible. By Antoinette Rahn

• The Artistry of Nature: Pursuit of Passions Results in Giologica. By Antoinette Rahn

In addition, you’ll find the following regular R&G columns: Bench Tips with Bob Rush, Rock Science with Steve Voynick, What to Cut with Russ Kaniuth, On the Rocks with Bob Jones, Artisan Alley with Erin Dana Balzrette, Picks & Pans, as well as an extensive Show Dates section, and the always popular Parting Shot.

The post Issue Highlights: June 2019 first appeared on Rock & Gem Magazine.