emeralds--3/5/25

05 Mar 2025

emeralds--3/5/25

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Today's selection-- from Precious by Helen Molesworth. The unlikely formation of emeralds.

“It was, therefore, an improbable chain of good fortune that brought the emerald in one piece from the Muzo mine in Colombia to Goldsmiths' Row. And it was more extraordinary still that something so precious and valuable should have survived intact for so long, to be seen and enjoyed by a modern museum audience.

“But perhaps none of these quirks of fate is as dramatic as the greatest chance happening of all: that such a handsome crystal ever existed in the first place. The formation of emeralds is a freak of nature. Their complex chemistry brings together beryllium, aluminum, silicon, and oxygen, which in its pure form produces colorless beryl, otherwise known as goshenite. It is only thanks to trace quantities of chromium, and sometimes vanadium, that the vivid green of emerald will appear. But beryllium and chromium do not naturally exist in proximity to each other. This means that it takes unusual geological events to unite these disparate elements: in some cases through an intrusive volcanic surge pushing minerals into rocks where they would not normally be, or, even more rarely, when the necessary elements are picked up at different points along their underground journey and finally deposited together in sedimentary shales to crystallize out into green gold. The latter is how Colombian emeralds form.

“These unlikely geological contortions explain why emeralds are found in only a handful of locations around the world, none more important than Colombia, whose propensity to produce perfect hexagonal crystals is historically unmatched. Not long after I had the opportunity to handle one of the finest early examples, the Cheapside watch, I had the equally exhilarating privilege of visiting the place from which it had emerged, the mine of Muzo. The town is located in one of two mining districts that sit in the shadow of the Andes, where emeralds have been sought and fought over for at least one thousand years. The Eastern Emerald Belt includes ancient mines such as Chivor: originally known as ‘Somondoco,’ or ‘God of Green Gems,’ and already eked out by the Spanish in the 1530s. The Western Emerald Belt contains the legendary mine of Muzo, kept secret from the Spanish a few decades longer and already in use hundreds of years before the arrival of the European invaders.' From a distance the town is picture-perfect, nestled in green hills and flanked by mist-shrouded mountains. Closer inspection reveals an earthier reality: centuries after the Spanish inva sion, the region was the subject of bloody fighting for control between competing families for decades until the 1990s (the ‘Green Wars’'), a conflict that has continued to sputter and smolder in the years since. When we visited, firearms had not long since been banned from the mines.

“The journey to get there can be almost as dangerous. From Bogota, we weaved our way through the mountains, often on barely passable roads that the rains wash away each spring, leaving only mud tracks. At one point, the local police took pity on us and escorted us part of the way. Our driver had a rosary swinging wildly above his dashboard: an object whose importance became more apparent as we realized his discreet habit of occasionally nodding off at the wheel.

Emerald crystal from Muzo, Colombia

“Inside the mine itself, the conditions are just as challenging: the temperature tops 40°C and the humidity 80 percent. Oxygen and electricity are piped in above your head as water flows freely by your feet. Ahead, workers are hammering wooden planks and beams into place, shoring up the next section of the tunnel. The surrounding shale is so dark and sticky that you are given clothes for single use, with little hope that, once stained, they can ever be made clean again.

You have entered an underground factory, a hidden hub of heavy industry thrumming several hundred feet below the earth's surface. Pipes buzz over your head, a constant hum accented by the hammering of drills and occasionally drowned out by the noise of dynamite. Having grown up caving in the Cheddar Gorge, a limestone valley in the southwest of England, I had long associated subterranean excursions with a peace and solitude that could never be matched elsewhere. That illusion of the underground as a place of quiet introspection was comprehensively shattered by my experiences visiting Muzo and other mechanized mines around the world. It is hard, heavy, sometimes heartbreaking work, dragging the world's most amazing treasures from their hidden homes.

“Yet when they are found, the results are extraordinary. On our way back from Muzo, we were invited to visit the mine's factory in Bogota, where a master cutter sat us down in front of a table laden with dozens of 100-carat stones—an astonishingly hefty haul thanks to a recently discovered emerald-bearing pocket. He demonstrated how these stones would be worked on, and in a moment it was like being transported back in time—as if I were watching the crystal that would become the Cheapside watch being made in front of my eyes. The thought of what it must have been like for the emerald-cutter of four centuries earlier to hold one of these untouched treasures in his hand was almost as exciting as holding the finished product itself had been.

“Emerald mining is a dance between the heavy tread of technology and the light fingers of the craftsman. Miners are blasting through the barriers of worthless rock that keep the precious contents hidden, but they are also observing with an expert eye: searching for white whispers of calcite on the dark shale that might—but only might—indicate that emeralds have crystallized within. More fragile than diamond, those crystals would be blown apart by explosives, so miners must move cautiously once they believe a deposit is close, swapping industrial methods for manual tools. It is dynamite one minute, delicate and dainty handiwork the next.”