Buried Treasure

A cave in a Mexican mine sparkles with the largest crystals in the world

Deep beneath the earth of a small town in northern Mexico lies a world of beauty few have ever seen. Giant crystals as long as a school bus fill a cavernous space nearly 1,000 feet below the surface. Known as the Cave of Crystals, the phenomenon dwarves those who study it and amazes all who see it.

Growing for hundreds of thousands of years underwater, the crystals weren’t discovered until 2000 when two brothers stumbled on it while excavating a new mining tunnel. Until 1945, the cave had been completely submerged, but mining operations drained the cave, exposing the larger than life crystals.

By studying bubbles inside the giant crystals, researchers have concluded that the amazing structures were built over thousands of years thanks to the optimal heat provided by nearby magma and the mineral-rich water that covered it for millennia. According to research published in the Proceedings of the National Academy of Sciences of the United States of America, gypsum crystals grow the slowest at nearly the exact temperature of the mine. This is what allowed the crystals to reach their enormous size but that has also made exploration of the cave tough. Temperatures in the cave can reach over 130 degrees Fahrenheit, high enough to kill a person in just minutes.

Scientists and preservationists are petitioning the Mexican government to protect the Cave of Crystals and have asked that officials claim it for a UNESCO World Heritage site. Naica mine is still a fully functioning operation today and researchers worry that damage may occur if the site is not properly protected. As of now, a steel door stands between the mines and curious collectors but no official laws are protecting it.

However, people aren’t the biggest threat to the crystals. Now that the cavern has been drained of its water, scientists fear that the giant structures could crack and break under their own weight.

Fun Facts

The mining company Industrias Peñoles pumps some 22,000 gallons of groundwater out of the cave per minute to keep it from re-flooding.

Initial exploration of the cave was done by Italian scientists and filmed for the 2010 documentary “Naica: Un Viaje a la Cueva de los Crystlaes,” or “Naica: Journey to the Crystal Cave.”

Italian explorers of the group La Venta Exploring Team made 12 trips inside the cave beginning in 2002 to explore and document the wonders inside.

The nearby Cave of Swords, Cave of Candles and Queen’s Eye Cave also boast large crystal formations.

In order to withstand the extreme heat in the cave, explorers wore specially designed cooling suits lined with ice packs and equipped with respirators.

Humidity inside the cave can reach 99 percent.