While the mine company is currently limiting visitation of the caves to scientific experts, mineral hunters have destroyed locks and broken into the chambers twice since they were first opened by mining equipment last April. One man was killed when he attempted to chop out a gigantic crystal that fell from the ceiling and pinned him.”The heat did him in” according to Fisher.
"We need more onsite protection of mine caves," said geologist Carol A. Hill, co-author of the book Cave Minerals of the World, who calls the new discoveries "by far the largest selenite crystals I have ever heard of."
Hill applauds the tourism plan. "Without it, the mining company would probably destroy the caves. Museums have enough crystals," she said. "It's important to preserve discoveries like this where they occur." The mining company plans to air-condition the caves before opening them to the public next year, Fisher said. He adds that reducing the heat gradually will not harm the crystals.
Officials of the Penoles Company, which owns the mine, kept the discoveries secret out of concern about vandalism. Not many people, however, would venture inside casually: the temperature hovers at 150 degrees, with 100 percent humidity. A person can stay inside the cave for only six to ten minutes before becoming disoriented.
These mountains are 200 million year old limestone massifs hosting networks of caves crossed by very deep hot and mineralized thermal waters. When these waters reached the relatively colder and closer to the surface environments they deposited much of their salt content as lead,zinc and silver .
Groundwater in these caves, rich with sulfur from the adjacent metal deposits, began dissolving the limestone walls, releasing large quantities of calcium. This calcium, in turn, combined with the sulfur to form crystals on a scale never before seen by humans.
*In addition to 4-foot diameter crystal columns 50 feet in length, the cavern contains row upon row of shark-tooth-shaped formations up to 3 feet high, which are set at odd angles throughout. This crystal form of the mineral gypsum, is known as selenite, named after Selene, the Greek goddess of the moon.
When Naica's ores are no longer viable, the mine is closed and the pumping is stopped, then the caves will be submerged - and the crystals will start growing again. The only reason humans can get in the caves at all is because of the ongoing pumping operations that keep them clear of water.
A forest of crystals, the largest on the Planet. An unreal world, beyond imagination, beyond a dream. A cave with a temperature of 50° C and 100% humidity; an infernal place, where man can survive just a few minutes. Still mostly unexplored.
