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by Micah Gilbert

There are many places where extraordinary natural specimens can be found, such as exotic Colombian mines for emeralds or the Moroccan Sahara Desert for dinosaur bones. While countries all over the world can yield phenomenal discoveries, our own lands here in the United States are also teeming with natural treasures of extraordinary quality and history.

I have explored a myriad of domestic mines and dig sites in search of remarkable minerals and fossils. As a result of international travel restrictions in the past year, my efforts to procure American specimens have accordingly increased, which has led me to many amazing discoveries here in the States. I’d like to share some of my experiences and knowledge regarding a few of the notable U.S. minerals that I have encountered.

One of my favorite minerals is the golden orange calcite from Tennessee. Perched atop a shimmering gray matrix of sphalerite, limestone and dolomite are enormous scalenohedral calcite crystals that exhibit a delightful, warm hue. They are found while mining for an economically important zinc ore known as sphalerite, and by sheer chance, certain pockets of exquisite calcite crystals are occasionally uncovered.

There have been a number of other instances in which rare mineral specimens are discovered by pure luck during the mining of ores and other valuable commercial materials. Deep within the coal mines of Illinois, there are fascinating disk-shaped pyrite formations ranging from the size of a small penny up to the size of a dinner plate. Dubbed “pyrite suns,” these curiosities are found adjacent to coal seams within layers of shale 200 to 300 feet underground, having formed a flat lateral shape due to compression. The metallic luster and brassy color of the pyrite suns contrast wonderfully with the dark gray hue of the shale matrix.

A short trip away in the same state are mines that yield stunning fluorite clusters of varying colors, including sky blue, vibrant yellow and deep purple. Their geometry is especially fascinating when the facets of the cubic crystals intersect and overlay in unusual ways. One of the miners I met had been collecting fluorite specimens for almost 50 years and had a display case dedicated to his most exquisite ‘fluorescent’ pieces. Under a UV light, these specimens glowed with vivid blue and violet hues that seemed almost otherworldly!

A few months ago, I passed through Colorado, which is probably the world’s most famous locality for rhodochrosite crystals. For decades, the goal of many mines in the area was to excavate silver ore, although over time the focus shifted to searching for rare rhodochrosite specimens. The luscious red rhodochrosite crystals stand out beautifully on their matrix of gray tetrahedrite and white quartz.

I also recently visited several mines within the Ouachita Mountains of Arkansas that were filled with breathtaking quartz crystals of unusual varieties. Some clusters sparkle with a vitreous luster and an aesthetic clarity that resemble fine diamonds. Some consist of giant crystals over a foot in length with beautiful iron oxide tints. It is remarkable to see these gem-quality crystals in their natural environments.

One of my most memorable experiences was watching the Arkansas miners remove clumps of mud off what appeared to be a mass of unappealing rock. As they scraped away the excess dirt and sprayed it with water, the rough brown sediment dissipated and what remained was a glistening cluster of clear crystals with perfectly preserved hexagonal points. It was a truly spectacular experience to see this miraculous beauty be uncovered for the first time in more than 250 million years.

Not only have many incredible minerals been found here in the USA but also quite a few extraordinary fossils. The fossilized teeth of the extinct megalodon shark can be found in the rivers and off the coast of the Carolinas. Estimated to grow over 50 feet in length, megalodon was the apex predator of the oceans for about 20 million years. Its fossilized teeth can reach over 6 inches in diagonal length and display a variety of colors and patterns depending on the mineral composition of the seabed in which they were buried. These buried “treasures” are highly sought after by divers and are among the most iconic teeth in the fossil trade.

Next time, I intend to share my experiences on some of the different fossils that I have encountered locally and abroad. *

Micah Gilbert is a geologist, paleontologist and gemologist with a trained eye for meticulously sourcing high-quality specimens that make for exquisite décor. He is the owner of Empressive Earth Gallery.

Empressive Earth Gallery explores domestic mines and dig sites for incredible finds

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