With lengths over 11m, the giant gypsum crystals found in Mexico are a great natural wonder.The Naica Mine of Chihuahua, Mexico, is a working mine that is known for its extraordinary crystals. Naica is a lead, zinc and silver mine in which large voids have been found, containing crystals of selenite (gypsum) as large as 4 feet in diameter and 50 feet long. The chamber holding these crystals is known as the Crystal Cave of Giants, and is approximately 1000 feet down in the limestone host rock of the mine. The crystals were formed by hydrothermal fluids emanating from the magma chambers below. The cavern was discovered while the miners were drilling through the Naica fault, which they were worried would flood the mine. The Cave of Swords is another chamber in the Naica Mine, containing similar large crystals.
The Naica mine was first discovered by early prospectors in 1794 south of Chihuahua City. They struck a vein of silver at the base of a range of hills called Naica by the Tarahumara Indians. The origin in the Tarahumara language seems to mean "a shady place".
Now, a Spanish-Mexican team thinks it can explain how these marvels acquired their immense form. The scientists studied tiny pockets of fluid trapped in the crystals and conducted back-up lab experiments. They report in the journal Geology that the solution from which the crystals grew must have been kept in a very narrow, stable temperature range. The researchers' analysis leads them to believe there are other dramatic caves waiting to be discovered in the Naica mine complex south-east of Chihuahua city. If the theory we propose for the 'genetic' mechanisms of the crystals is right, then would not be surprised if miners find more of these caves in the next few years.
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