Lesser Known Wonders Of The World: Giant Crystal Cave (Mexico)

The cavern of Giant Crystals was found by two brothers who were digging in the Naica lead and silver mine. The cave lies 1000 ft below the Chihuahua Desert.

They are formed from groundwater saturated in calcium sulphate which, warmed by an intrusion of magma about a mile below, began filtering through the cave system millions of years ago.

When, about 600,000 years ago, the magma began to cool, the minerals started to precipitate out of the water, and over the centuries the tiny crystals they formed grew and grew until 1985, when miners unwittingly drained the cave as they lowered the water table with mine pumps.
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Because the crystals resemble giant icicles, the picture suggests it must be very cold inside the Cave of Crystals - but appearances can be deceptive.

In fact, the temperature is a sweltering 112F, with a humidity of 90-100 per cent.

This is why cavers wear protective suits and carry backpacks of ice-cooled air.

Text: Daily Mail