What is Amber?

Amber is fossilized tree sap or resin. Nearly all amber comes from coniferous trees. The resin comes mainly from damage to the bark of the tree. For instance, when a live pine branch is broken, sap runs out of the wound. This yellowish resin hardens to protect the tree and prevent further damage.

The resin also has antiseptic properties to help heal the tree. The resin is also very sticky and will trap insects and other debris such as seeds and leaves that may encounter it. In some cases, air will become trapped as the sap flows, creating bubbles. On rare occasions, water is trapped in the bubbles creating enhydros, liquid water inside the air bubbles. Paleontologists can study these air bubbles and water to see what the ancient environment was like.

The resin also may have flowed several times creating layers trapping various insects on different layers. When an abundance of resin flows, it may even drip and fall to the forest floor trapping dirt, leaves, seeds and other organic material.

Ancient Amber

As ancient trees died and fell to the ground or individual pieces dried and fell to the forest floor, resin-covered trees were washed into streams and rivers and were buried in sedimentary deposits.

Amber dates from around one million years ago to around 300 million years ago, so there is a wide variety of organic matter that has been trapped. Trapped organic matter is called an inclusion.

Where is Amber Stone Found?

Amber can be found in some parts of the world in great abundance. When found, it can have many shapes including irregular nodules, blobs, large thin sheets and even a drop-like shape.

The Baltic region produces most of the commercially available amber. Areas around Russia, Lithuania and Poland are major sources of amber.

The area of what is now the Baltic Sea was dry land millions of years ago. The area was populated with animals, plants and conifer trees. Later, when large amounts of ice melted, the sea level rose and began washing amber and other fossils onto the beaches.

Today, fishermen with their drag nets are hauling in Ice Age bones and other fossils as they fish.

So much amber has been found that many European palaces are adorned with amber lamps, furniture, picture frames, artworks, sculptures and jewelry. Entire rooms have even been filled with amber.

Amber Properties

Amber has a Mohs hardness of 2 to 2.5.

It is an organic substance and it does retain its chemical composition for some time. As it hardens the resin molecules link with others to form larger molecules in a process called polymerization. This slow process can take several tens of thousands to millions of years.

After it polymerizes, the amber becomes less soluble in various organic solvents. This means that it will not become sticky when in contact with toluene, acetone, alcohol or other solvents. Copal or what some call “young amber” will get softer and sticky when in contact with organic solvents. Copal is sometimes desired for jewelry making as real amber is far too brittle and tends to shatter.

Young amber is not considered true amber and comes mostly from Columbia and Madagascar. True amber for lapidary uses comes from the Baltic and the Dominican Republic. Amber can be polished and often it will reveal treasures inside that can tell us about prehistoric times.

This story about amber stone previously appeared in Rock & Gem magazine. Click here to subscribe. Story by Joseph “PaleoJoe” Kchodl.

The post Amber Stone: Nature’s Insect Death Trap first appeared on Rock & Gem Magazine.

Beautiful Petoskey Stones

Walking along the northern Lower Peninsula shorelines of Lake Huron and Lake Michigan, it is easy to see this fossil’s natural attraction on people. Looking into the water, one can sometimes see this coral, rounded by relentless waves, worn smooth showing its beautiful internal structure. It is easy to see that rockhounds, jewelry makers and almost everyone would be taken by this attractive fossil.

Once removed from the water, however, it quickly dries and loses its bright polished shine. To achieve that permanent shine, it is necessary to polish the rock by grinding and sanding it and finishing it with a polishing compound to bring out the beautiful luster of the stone.

What Corals Make Petoskey Stones?

Petoskey stones are fossilized corals. There are at least nine species of Hexagonaria, but the only true Petoskey Stone is the H. percarinata. These corals are marine organisms that are made up of many, sometimes thousands of hard calcium carbonate exoskeletons called corallites. Each corallite contains a polyp – an individual multi-cellular animal.

There are two major types of corals – solitary corals growing by themselves, and colonial corals, growing in a tight community of genetically identical polyps. The polyp is the actual living individual creature that inhabits each corallite. As the coral grows, it extends the calcium carbonate exoskeleton and seals off part of the base.

Symbiotic Relationships

Corals live in a symbiotic relationship with a variety of marine algae. Although corals have stinging tentacles and are able to capture food such as zooplankton, the algae provide the energy corals need to survive.

Food is captured by tentacles and brought down to the center where the mouth and stomach are located. The algae use a process called photosynthesis to provide additional energy to the coral polyp. In turn, the hard calcium carbonate exoskeleton of the coral and stinging tentacles provide protection for the algae.

The coral polyp produces waste products that the algae needs for its survival. Because sunlight is needed for the algae’s photosynthesis processes and sunlight only penetrates the ocean to a certain depth, corals normally grow in shallow waters from 30 to 150 feet.

Hexagonaria Coral

Hexagonaria coral is a colonial marine animal that lived in warm shallow salt-water tropical seas. Prehistoric Michigan was once such an environment. During the Devonian Period some 419 -358 million years ago, Michigan was located much closer to the equator.

Much of Michigan’s bedrock is made up of huge limestone beds that underlie the surface soil. These large tracts of limestone bedrock are the remains of ancient coral reefs that filled the sea that once covered what is now Michigan. Ancient coral seas were full of a variety of creatures that included but were not limited to, corals -both solitary and colonial.

Each corallite of the Hexagonaria is made of a sometimes five but usually six-sided compartment which adjoined the others in the colony and created the elaborate six-sided hexagon. The radiating lines one sees in the Petoskey Stone are the septa and theca. The septa are the lines of division between each corallite and the theca are the internal radiating lines. These patterns of hexagon shapes and radiating lines are what will gives the Petoskey Stone its uniqueness among rocks.

Finding Petoskey Stones

The Hexagonaria are found across Michigan along lakeshores and rivers in the sediments commonly called the Traverse group. They are rounded fragments of the coral Hexagonaria. Some of these coral reefs still lie beneath the ground and some under the water of Little Traverse Bay.

Because of the wave and abrasive action of the sand, these stones are rounded and washed up on the beach. The action of ice moving also brings these stones into shallow water. The best time to hunt for Petoskey stones is in the spring as soon as the ice melts. But beware, it is a cold time to search! I have seen locals donning dry suits and walking in waist-deep water as ice floats by and picking up the stones before they even reach the shore.

How Did Petoskey Stones Get Their Name?

The name Petoskey is said to come from an old Odawa Indian legend. It is said that a French fur trader, Antoine Carre, came to Michigan traveling extensively in the area now known as Petoskey where he met and married an Odawa princess. In time, he was adopted by the local Odawa tribe and eventually was made their chief.

It is further told that in the spring of 1787 traveling with his wife on his way from near present-day Chicago, he camped near what is now Kalamazoo. During the night, his wife gave birth to a son. Legend says that as the morning sun rose, the sun’s rays fell upon the infant’s face, and his father pronounced his name shall be Petosegay. The translation of the Odawa Petosegay means sunbeam or rising sun or rays of dawn.

Petosegay became a fur trader like his father and also became quite wealthy. He owned much land in the Petoskey area, and a community was settled on the shores of Little Traverse Bay. The present location of the city of Petoskey stands as a tribute to Petosegay. Because these rounded and water-tumbled fossils were found in great abundance on the shores of Little Traverse Bay, they became known as Petoskey stones.

Becoming a State Stone

The Petoskey stone was made the state stone of Michigan by legislative action. Then-Governor George Romney signed House Bill 2297 in 1965. This legislation elevated this fossil to the prestigious position it now holds around the world. For visitors to the Great Lakes, a Petoskey stone find is often a must-do!

This story about Petoskey stones appeared in the September 2021 issue of Rock & Gem magazine. Click here to subscribe! Story by Joseph “Paleo Joe” Kchodl.  

The post Petoskey Stones: Where & How to Find Them first appeared on Rock & Gem Magazine.

Rising from the Red Mountain in the center of the Lhasa Valley, Potala had been the winter palace of the Dalai Lama since the 7th century. Rockefeller sketched its grandeur on the back of an envelope that he shared years later as governor, with architect Wallace Harrison (designer of Manhattan’s Rockefeller Center). He envisioned a modernist plaza, similarly built atop a three-mile-long escarpment of a 1,200-foot tall limestone cliff, with a panoramic view of four mountain ranges: the Adirondacks, Berkshires, Green Mountains and Taconics.

Fortunately for fossil hunters and geologists, Rockefeller’s plans for urban renewal were nixed because of the area’s lack of proximity to the city or downtown state offices.

Today, preserved within John Boyd Thacher State Park, the Helderberg Escarpment’s incomparable fossils and limestone layers share the story of land once covered by a shallow sea and brimming, for millions of years, with marine life.

By the Sea, The Sirulian Sea

The escarpment had inspired Rockefeller to think “up” (Heldeberg is Dutch for ‘clear mountain’) but savvy fossil and rock buffs will see how the good stuff starts at the bottom, where the “Cliffs Higher Than the Palisades” found their origin as a salty seabed.

The Erie Lowlands-Allegheny Plateau consists of flat-lying layers of sediment rock from the Late Silurian and Devonian periods, 420-380 million years ago.

The oldest are the rocks of the Upper Silurian (dolostones, evaporites and shales) and limestones of the Helderberg Group. These tell of a warm, shallow sea covering most of New York. Above a terminal dominated by carbon rock, an unconformity records the sea’s retreat and the beginning of erosion to the exposed Helderberg Group.

Helderberg Workshop, a nonprofit organization at the foot of the escarpment, says the exposed cliff was “essentially the shore of an ancient sea,” a vertical stretch of sedimentary rock, laid down by the ebb and flow of water over half a billion years, that by the 1800s was destined to become a world-famous geological landmark and hotbed for the scientific query.

Fantastic Fossils

Helderberg Escarpment fossils chronicle a geological history that began intriguing scholars worldwide in the early 19th century. So, when you go, don’t miss a stop by the Thacher Park plaque erected in 1933 to 16 great inquiring minds that found inspiration and information there: “In memory of those pioneer geologists whose researches in the Helderbergs from 1819 to 1850 made this region classic ground.”

Among them: American geologist Amos Eaton (1776-1842), founder of the modern scientific prospectus in education; Eaton’s surveyor and mineralogist, James Eights; paleontologist James Hall (1811-1898), discoverer of the first North American fossil reefs; William W. Mather (1804-1859) author of The Geology of New York-Part IV; and Sir Charles Lyell, a Scottish Baronet (1797-1875), whose evolution uniformitarianism posited that the formation of the Earth’s crust was through small changes, occurring over vast periods, according to known natural laws.

Fossils here include brachiopods, coral, crinoid stems, cystoids, and trilobites. Brachiopods have hard “valve” shells on their upper and lower surfaces (unlike left/right placement on bivalves) and include nearly 30,000 fossil species with less than 400 surviving today.

Crinoids mislabeled “sea lilies,” are not plants but animals, with a calyx (skeleton) that provides a stony anchor to hold it fast to a sea floor.

And who doesn’t love a good trilobite?

Certainly, Charles Emerson Beecher did who wrote, in 1893 in the American Journal of Science, “Attention has been called to the perfection of fossils in the siliceous limestones from a limited locality in the Helderberg Mountains. Proper collecting yields quantities of the most delicate and exquisitely preserved remains. The conditions of preservation are such that not only are large and strong species preserved, but also the smallest and young of many in all stages of growth.”

Indian Ladder Trail is probably the park’s most popular hiking choice. It was named after native trails that originally traversed the escarpment that led to settlements in the Schoharie Valley and later, during the Revolution, to caves providing refuge for loyalists. Look for dark grey-to-black chert nodules (silica-rich lumps originating from the diagenesis of shelled organisms), which were used as arrowhead material by local indigenous nations. Thin grey, black, or brown shale beds along the trail hold small mollusks and snails. Look up and you may find brachiopods, crinoid stems, and (if lucky) a black, dime-to-quarter-sized trilobite or two.

Thank You, Mr. & Mrs. Thacher

Who were John Boyd and Emma Treadwell Thacher, and why is a park protecting a half-billion-year-old geologic treasure named after them?

The interest originally generated in the cliffs by the scientific community — leading one to call the Helderbergs “a key to the geology of North America” – began attracting tourists. The bucolic mountain valley below the escarpment started, thanks to a burgeoning Delaware & Hudson Railroad, to look like an uncomfortable plethora of boarding houses, hotels and campgrounds.

Enter former Albany mayor and state senator, J.B. Thacher (1847-1909). In 1906, he and Emma Treadwell Thacher (1850- 1927) began acquiring property along the escarpment to protect it from development.

The couple owned numerous ridge-top parcels before his passing three years later.

Thacher, an inveterate collector, also had an impressive array of autographs that included every signer of the U.S. Declaration of Independence, which Emma later donated to the Library of Congress.

She also donated 350 of their acres to New York State for a public parkland. In 1914, the legislature delegated management to the American Scenic and Historic Preservation Society (ASHPS) so that “the lover of nature, the geologist, the seeker for inspiration can here make interesting explorations of the wonders of nature…”

In 1924, when New York State passed a $15 million bond to develop a state park system, Thacher Park received $25,000 for development. The state park plan, which sought to link urban populations with scenic resources, called Thacher “the key park serving the Capital District.” This prompted plans for additional improvement and, by the 1960s, its parking lots “accommodated record-breaking weekend crowds.”

By the mid-1990s, the Open Space Institute picked up where the Thachers had left off, identifying and acquiring more key parcels along the escarpment and conveying them to the state as additions to the park. In a decade, they more than doubled the park’s size.

Exploring Today

While collecting fossils is prohibited in state parks, you’ll find all the same opportunities for scientific inquiry and exploration of the natural world that has drawn visitors for centuries to one of the richest fossil-bearing formations found anywhere.

As recently as April 2022, Thacher Park was named a Best Of The Capital Region winner and “an adventure every time.”

Fossils are easy to spot on rocks in streambeds, in stone walls along the Overlook and in exposed rocks on the Cliff Top Trail.

Before you strike out on one of more than 25 miles of trails, check out the Visitor Center’s geological and historical exhibits showcasing the Helderberg Escarpment, and the panoramic Helderberg Room, a favorite spot for weddings and celebrations.

Outdoors, camping for tents or RVs is available at any of 140 sites at Thompson’s Lake Campgrounds. Sport climbing is available with a signed permit application.

A Wild Play Adventure Course has 60 aerial games, a 40-foot jump, and 15 zip lines. A New York State Park vehicle entrance fee of $6 is collected 9 a.m. to 5 p.m. daily, May 1-October 31.

In 1905 – half a billion years after a sea floor became a limestone cliff – Thacher wrote, “The writing of a man, it is held, is the most perfect relic he leaves behind.”

One visit to the geological and paleontological wonder that bears his name (and inspired a Rockefeller) and it’s fair to say that both underestimated the power and perfection, millennia after millennia, of the Helderberg Escarpment.

This story about the Helderberg escarpment fossils previously appeared in Rock & Gem magazine. Click here to subscribe. Story by L.A. Sokolowski.

The post Helderberg Escarpment Fossils first appeared on Rock & Gem Magazine.

Varieties of Fossil Ammonites

Smaller-sized fossil ammonites are often used to carve out the inner cells to inlay stone material. The larger size fossils are cut to form cabochons.

The Cleoniceras Ammonites from the north side of Madagascar are the most sought after for their size and beautiful root beer iridescent colors with intertwining fern leaf patterns. The golden-brown coloring is from the fossilization of 120 million years of water mineralization replacing the shell with calcite. This material is on the soft side, but still stable enough to work.

Purchasing Considerations

There are several factors to consider when searching for materials to purchase:

• If you have not seen a whole ammonite in person, know that both sides are uneven. Spirals on the inside are tighter and thinner than at the opening of the shell.

• A fossil ammonite is entirely curved with no flat surfaces. This can create a challenge in the cabbing process.

• Look carefully at both sides of the ammonite to see how much working area you will have since you will be cutting it in half to use both sides for cabochons.

• Gray patches are usually porous, crumbly and unusable, so focus on the areas with color.

• Hollowed cells inside can mean you don’t have enough material to cut cabs unless the cells are filled or backed.

Getting Started

First, cut the entire ammonite in half creating two identical portions to use. Then examine the inside to see if it needs to be filled with epoxy or backed for stability.

Once you have the two sides cut and prepared, you are ready to draw out your design. Carefully choose areas that can be cabbed that don’t have a great deal of an arch across the top or an uneven area that will have to be ground down to an equal height causing you to lose the top coloring on a portion of your cab. Remember that the outer layer is much darker, iridescent and thin.

Because it’s comprised of calcite, it’s easy to grind through the top layer and lose that lush darker color. It will sand down too far yielding a light golden yellow and the pattern may be lost. To make sure this doesn’t happen, cut your preforms to the shapes you desire, and grind the backside flat as you attempt to make an even girdle height around the sides.

Cabbing Fossil Ammonites

It’s best not to use heavy coarse grit wheels and go right to the 280 soft resin wheel to gently dome the top of your cab and finish shaping it. There’s not much you need to do, since the 280 will grind this soft material rapidly. Do only the bare minimum at this stage!

Once you have it shaped and domed, allow the 600 grit wheel to remove any remaining scratches. Be sure to dry your cab off thoroughly and check for scratches and to see if you are removing too much of the top layer.

Now you can move forward to the 1200 grit stage, continuing to use a gentle touch. Even the 1200 grit can remove material when it’s this soft. To finish, use a 14k grit soft resin wheel. It should bring your piece to a beautiful gloss finish with no need to go any further.

If you desire to attempt a mirror glossy finish, you can use Zam polishing compound and a polishing tip on a Dremel. Do only the bare minimum so you don’t overheat and crack your cab.

This What to Cut column about fossil ammonites previously appeared in Rock & Gem magazine. Click here to subscribe! Story and photos by Russ Kaniuth.

The post What to Cut – Fossil Ammonites first appeared on Rock & Gem Magazine.

Editor’s Note: This RG Kids profile is a wonderful example of how developing an appreciation for fossils and rocks as a youth can bloom into a life-long passion and remarkable career.

Steve Brusatte is a respected professional paleontologist with an appointment at the prestigious University of Edinburgh in Scotland. He travels the world seeking dinosaurs, has published articles in major scientific and popular journals, has assisted with documentaries about dinosaurs, has authored books including the leading textbook Dinosaur Paleobiology, and just last year published yet another book that you can find in your local bookstore, The Rise & Fall of the Dinosaurs. All this by age 35!

But once, Steve was an ordinary teenager with a passion for movies, music, and baseball. If anything, while writing sports articles for his local Ottawa Daily Times newspaper in small-town Illinois, he dreamed of becoming a professional journalist. Yet by 2002, at age 18, he had written over 100 articles and papers not on baseball but fossils, with many published in magazines for amateur enthusiasts. He had even published a book, Stately Fossils.

Discovering a Passion for Paleontology

He credits his younger brother Chris for igniting this explosion of activity. Chris was 10 years old and wanted to write a book on famous paleontologists. He called on brother Steve, 14, to help. From then on, there was no looking back! Steve acquired books and wrote and wrote and wrote.

Along the way, he struck up an online friendship with adult fossil enthusiast Allen Debus, who connected him with Lynne Clos. Lynne published a monthly magazine, Fossil News: Journal of Avocational Paleontology. Allen and Lynn encouraged Steve, at the age of 15, to write monthly articles, first for a “Kids Corner” section, then for a series to describe the official state fossil of each state in the U.S. He soon had quite the portfolio of publications.

During family vacations, Steve cajoled parents Jim and Roxanne to haul brothers Chris and Mike and him to any museums along the way, and it was at a museum where, at age 15, Steve met his youthful hero, Paul Sereno. A professor at the University of Chicago, Paul had become something of a rock star in the world of dinosaur paleontology, and Steve thrust a manila envelope of his articles into Paul’s hands. Paul suggested they stay in touch. A mere three years later, they were not only in touch, Steve was Paul’s student and soon became Paul’s coauthor on professional papers.

Study, Research, Search

Since then, with the generous assistance and kind encouragement of many other heroes, Steve has enjoyed a whirlwind career that has taken him to further academic studies at the University of Bristol, Columbia University, the American Museum of Natural History, and elsewhere. He collaborates with major figures in the world of dinosaur paleontology, travels the globe, and digs up new dinosaur species.

He recently became a father, with the arrival of his son Anthony, and thus has a

whole new generation to inspire and encourage, just as so many inspired him.

I’ve enjoyed two wonderful opportunities to meet Steve while visiting my own daughter’s family in Edinburgh, Scotland, and here are Steve’s words of advice to the new generation:

“Never stop exploring the world around you. If you’re passionate about something, go for it. Find a way to keep your interests and dreams. Maybe you can make a career of it, maybe not. But the important thing is to be enthused and engaged. Who knows where it will take you!”

The post Spotlight on Juniors Plus: Steve Brusatte first appeared on Rock & Gem Magazine.

How Our Inner Core Rescued Our Planet

Earth has a strong magnetic field that shields us from so-called solar wind and radiation and, thus, protects life—protection that, apparently, long ago disappeared on our now-barren Martian neighbor. A study in the February issue of Nature Geoscience journal suggests that we very nearly lost that protective magnetic field, just as Mars did, until relatively recently geologically speaking.

How relative is recent when it comes to geology? About 565 million years ago! Until then, we had a molten iron-nickel core, and convection from it powered our magnetic field. But that power began to fade toward a potential collapse a half billion years ago, or right about the time that complex life was primed to emerge on Earth.

Earth consolidated as a molten orb 4.54 billion years ago and has been losing heat ever since. It was the heat deep down inside our molten core that helped drive our magnetic field. As that heat dissipated, the magnetic field grew increasingly weak and unstable, but then, relatively quickly per the recent study, the very center of our core crystalized and solidified while remaining surrounded by molten iron-nickel. The combination apparently created a geodynamo that not only rejuvenated but reinforced our magnetic field, making it stronger than ever.

An Ancient Version of the Platypus?

Today’s platypus is one weird critter. So weird that when first reported from Australia, many European scientists refused to believe it, even when shown a taxidermed specimen in 1799. An egg-laying mammal with venomous spurs, a duckbill, a beaver-like tail, the feet of an otter, and tiny little eyes? Surely, such a creature was an elaborate hoax sewn together and invented by some warped imagination!

It turns out, the platypus may have had a weird precursor. Welcome, Eretmorhipis carrolldongi. This marine reptile swam the seas of what is now central China 250 million years ago. Per an article in the journal Scientific Reports, just like the platypus, this aquatic critter had tiny little eyes and tiny little ears that would have been of little use in seeking prey. Instead, it is believe to have hunted using touch and/or electric fields, facilitated perhaps by hair cells designed to detect movement, much like today’s platypus.

Never rule out the weirdly wonderful, inventive and creative power of nature!

What Keeps a Martian Lake Liquid?

In a past article, I reported on a study suggesting the existence of a liquid lake some 20 kilometers wide 1.5 kilometers below the southern polar ice cap of Mars.

This was based on a study reported in 2018 by a team led by Italian planetary scientist Roberto Oresei. If there is any place on our neighboring planet that might harbor Earth-like life, this might be it! But what keeps that lake liquid on frigid Mars?

Scientists have suggested dust on the ice cap (thus providing insulation), salts dissolved in the water (thus lowering its freezing point), and more. But none of the ideas proposed thus far seem to pass muster when put through rigorous scientific analysis. Instead, planetary scientists Michael Sori and Ali Bramson of the University of Arizona recently suggested in Geophysical Research Letters the existence of an underground chamber of magma.

However, like true scientists who follow evidence wherever it may lead, the authors are circumspect and modest about their proposal. Says Bramson, “Honestly, we’re not sure.” For instance, other radar searches fail to even detect an underground lake, much less a magma chamber. Would that all of us learn a lesson from Bramson’s forthright appraisal, a lesson of modesty, humility, and a frank and honest search for truth based on evidence as we proceed through life!

The post Earth Science In the News: Earth’s Core, Ancient Platypus first appeared on Rock & Gem Magazine.