Until you notice the orange-suited men clambering around, it’s hard to grasp the extraordinary scale of this underground crystal forest. Nearly 1,000ft below the Chihuahua Desert in Mexico, this cave was discovered by two brothers drilling in the Naica lead and silver mine. It is an eerie sight. Up to 170 giant, luminous obelisks – the biggest is 37.4ft long and the equivalent height of six men – jut across the grotto like tangled pillars of light; and the damp rock of their walls is covered with yet more flawless clusters of blade-sharp crystal.
The Naica mine is located 100km to the North East of the city of Chihuahua. The crystals are selenite (gypsum). “The most important identifying characteristic is how soft gypsum is [2 on Mohs Scale], as any variety of gypsum can be easily scratched with a fingernail. Also because gypsum has natural insulating properties, all varieties feel warm to the touch.”-wiki
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.
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.
That does not make sense to me. Cave temperatures are supposed to be the average yearly temperature of the surface. Since the Mexican desert would be cold at night, the temperature should be about half this, right? Well, according to nature, parts of the desert are more than 120F, so this cave must be under one of the hottest regions. “The Chihuahuan Desert’s variation in elevation (between 1,000 and 10,000 feet) and temperature (from more than 120 degrees Fahrenheit to below-freezing temperatures)”
This is why cavers wear protective suits and carry backpacks of ice-cooled air. Such conditions, and the fact that it takes 20 minutes to drive to its entrance through a twisting mine-shaft, haven’t deterred would-be looters – one of the crystals bears a deep scar where someone has tried, and failed, to cut through it. But the cave has now been fitted with a heavy steel door, the better to preserve this beautiful wonder for generations to come. – dailymail
Thick, blocky crystals line the interior of a cave called the Shark’s Mouth. Recently found not far from the Cave of Crystals, this cavern confirms the belief of geologists that numerous crystal-bearing deposits still await discovery in the rock. Because miners had been using explosives nearby, many crystals in the Shark’s Mouth were covered with dust.