October 4, 2023

One day in October 1820, two young men, Elijah Hamlin and Ezekiel Holmes, were hiking on a hill in Maine called Mount Mica when they discovered a bright green stone on the ground. They picked it up and started looking for others, but it got dark. It snowed the next day.

When they finally returned in the spring, they found the hill littered with such stones that have been identified as tourmaline, a semi-precious stone valued for its variety of colors. Word spread. In 1879 a gentleman geologist and globetrotter named George visited Kunz. He gave some pieces to a businessman named Charles Tiffany, who hired him straight away. One of Tiffany’s board members was JP Morgan, the banker and robber baron who started buying tourmaline and other jewels through Kunz. Much of this collection ended up in the American Museum of Natural History.

I was introduced to Morgan’s tourmaline along with the original tourmaline found by these hikers (made into a watch tag labeled Primus or “first”) when I recently visited the newly opened Allison and Roberto Mignone Hall of Gems and Minerals .

Recognition…Geological survey of Maine

Next to the tourmaline, I stared at a dazzling collection of crystals, some the size of tree stumps, others dainty enough to grace an Oscar nominee’s clipping on the red carpet.

Minerals, as a sign on the wall helpfully told me, are ordered arrangements of atoms and molecules. “Most of the solid matter in the universe is made up of minerals,” said George Harlow, a geologist and longtime curator who patiently showed me around and seemed able to read rocks as easily as the morning paper.

“People don’t know ice is a mineral,” he remarked. And snow, he added, is a sediment.

There are roughly 5,000 types of mineral on earth, and I hardly know the names of them, although they form the substance of the world on which we evolved and, presumably, the distant worlds on which we hope to discover more life one day.

They tell age-old stories: of continents colliding, of mountain ranges that rise and wear away, of ocean basins that fold and crumble, of Hadean chambers that produce crystals of gas and liquids. Some of these minerals are almost as old as time itself. The nanodiamonds found in stardust could have been formed in supernova explosions that occurred just a few hundred million years after the Big Bang, said Dr. Harlow.

I felt a familiar cosmic atmosphere when I entered the hall. There in front of me, two meters high and in a rocky shell like an egg broken open by the gods, lay a nest of purple amethysts, the light of a galaxy.

A geode that formed in Uruguay 135 million years ago when mineral-rich water seeped into an underground chamber, perhaps a bubble in the magma, and then crystallized on the walls. Behind it was another geode, another purple galaxy facing the main exhibition, a concrete manifestation of how the real universe – reduced to bare points or less in astrophysical data – actually works.

All minerals are formed by the same fundamentals: water, heat, and pressure. But like Tolstoy’s unhappy families, each rock has its own story. The earth’s crust has broken into plates called tectonic plates that, when floating on molten magma, crash into one another, bulge into mountain ranges, merge into continents, and separate into seas.

Geology is biological fate: whatever minerals land or are deposited in a place, determine millions of years later what or who can make a living there. Trout prefer Montana, my fly-fishing friends tell me, because the streams flowing through limestone create pleasant conditions for our freshwater quarry.

Millions of years ago the Mississippi Valley was an inland sea. As geological forces pushed the ocean floor up, water – enriched with ores such as zinc and lead – seeped through the porous carbonate rock that made up the ocean floor, leaving deposits in pockets and veins. In 1894, a miner named James Roach broke into a cave 25 meters below Joplin, Missouri. The walls, ceiling and floor were lined with calcite crystals, a form of carbonate. He and his family turned it into an underground dance hall and tourist attraction, Crystal Cave. It reclaimed groundwater in the 1940s.

One of the most powerful stones on display at the museum is a four-foot-tall, 7,756-pound chunk of gray-green rock called beryl, from which both emeralds and beryllium are derived.

In 1930, this stone was a four-meter-high lump in the Bumpus Quarry in Maine that blocked access to a huge vein of premium feldspar that the quarry owner was keen to mine. He blew it up the day before Mr. Kunz’s arrival with an offer to buy it for the Natural History Museum. The museum bought a few fragments that stood for many years.

It so happens that beryl itself is valuable as a source of lithium and beryllium, a light element born in stars and collisions with cosmic rays. The mirrors of NASA’s upcoming James Webb Space Telescope are made of beryllium.


On our tour, Dr. Harlow more history in another Goliath rock, an amphibolite slab from Gore Mountain in New York State. Old geochemical fault lines could be seen in the plate, along with an array of grenades, the ruby-colored official gem of New York State. They tracked the old wall, now lost to the time it had grown on, and offered to Dr. Harlow added more sentences in the Book of Ancient Cataclysms.

I walked over to the gem alcove to marvel at the beauties of the ball, including the Star of India, another find by the resourceful Mr. Kunz, this time on behalf of JP Morgan. Finally, I returned to the pair of purple geodes that stood like star gates at the entrance to the exhibit.

Unfortunately, their splendor does not last. Amethyst, a form of quartz, is usually yellow or gray, Dr. Harlow. The purple was the result of radiation damage, likely from the surrounding rocks where the amethysts formed, and would most likely return to its original color at some point. Even stones are not immortal.

On the other side of the hall, right in front of the star gates, was another sign of mortality: a slab of petrified wood from an ancient sequoia tree. Museum officials have counted 884 rings and dated the tree to 33 million to 35 million years ago. In the meantime, chemistry has worked its magic and silicate minerals replaced the cellulose in the wood and at the same time set the growth record.

Dr. Harlow pointed to a similar sized slab of sequoia that was cut down around a few corners in the Hall of American Forests in 1891. The line between vegetables and minerals is not as strict as you might think, he reflected: “There is no life without minerals. Life has learned how to make minerals in teeth, bones and shells. ”Eventually, life returns to minerals in the form of fossils and petrified wood.

“People think this is separate,” said Dr. Harlow. “It’s all part of a whole.”