People have used gypsum for a variety of purposes for thousands of years. All kinds of varieties of this mineral are used, among other things, as a soft ornamental stone. Sometimes gypsum is found in the form of fairly large crystalline formations. But at the turn of the 21st century, a deposit of surprisingly large crystals was discovered — in fact, real giant columns.
A unique hiding place of nature
A cluster of gypsum crystals was discovered under the city of Naica in Mexico, in the state of Chihuahua, in a limestone layer at a depth of 300 meters underground. Somewhat higher, back in 1910, during mining operations, a small cavity with selenite crystals (a type of gypsum with a fibrous structure) about a meter in length was covered. It was called the Cave of Swords.
And 90 years later, miners, digging another tunnel, came across a vast cave with many huge crystals, the largest of which are 11 meters long. Their mass reaches tens of tons. The cave was filled with hot water, or rather, a mineral solution. After the cave was drained, the selenite giants appeared in all their splendor.
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Where did gypsum come from?
How were these wonderful crystals formed? They owe their formation to the proximity of the magma chamber, which was located under the cave due to the penetration of magma through the cracks of an ancient geological fault passing directly under Nike.
Under the influence of magma, underground waters were heated and enriched with minerals. Anhydrite was dissolved in hot water — a mineral related to gypsum. Chemically, it is also calcium sulfate, but, in contrast to gypsum, anhydrite crystals do not contain bound water. If the temperature of the solution is above 58 degrees, anhydrite precipitates from it and crystallizes, if below — gypsum.
Ideal criteria
It so happened that the temperature of the water in the cave above the cavity with magma was slightly below this boundary, and the formation of gypsum began. It is important that such requirements persisted long enough and allowed many beautiful white, slightly translucent crystals to grow to gigantic sizes — on average up to 5 meters in length.
A 2011 study found that amazing selenite columns had been growing here continuously for at least half a million years, and most likely much longer. As for the small Cave of Swords located above, the water in it apparently cooled much faster, and further growth of gypsum crystals stopped.
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Dangerous beauty
Immediately after pumping water from the Cave of Crystals, it became clear that this was a very inhospitable place. Not only is it extremely hot here (air temperatures hover around 50 degrees), but the humidity level is close to 100%. The combination of these conditions poses a great danger to a visitor who dares to linger in this underground palace for even a few minutes.
The water with which the local air is saturated begins to condense in the human lungs, since they are much colder. For this reason, lovers of extreme travel to unusual corners of our planet should not rush to pack their backpacks: visiting these crystalline wonders is currently impossible. The cave is closed to travelers. And this is for the better — after all, with all the splendor of the natural treasury, it threatens those who carelessly invade it with an irreparable outcome.
Age of Exploration
At first, the cave explorers limited themselves to short-term forays, the duration of which, for safety reasons, did not exceed 10 minutes. Then, using special equipment — suits protecting from overheating, and often respirators — the scientists were eventually able to extend their visits slightly. With the use of respirators connected to packs filled with ice and supplying cooled air for breathing, excursions lasting from 15 to 60 minutes became possible.
During expeditions to the Cave of Crystals, carried out in 2008 and 2009. with the participation of the head of the NASA Institute of Astrobiology Penelope Boston, microbial life forms were discovered that were trapped inside one of the crystals. The tiny organisms, trapped in an air bubble, may have remained dormant for 50,000 years before scientists discovered them.
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Removing water from this cave, which had to be done continuously, was a boon to the scientific community. But, unfortunately, this is fraught with bad consequences for the unique selenite giants. In 2017, drainage of the cave was stopped, and groundwater began to fill its space again. Before this, the crystals were exposed to the destructive effects of air for almost two decades.
A series of experiments carried out on samples collected in the cave show that the structural integrity of the crystals was at risk. However, now that the water is returning, these masterpieces created by nature have the opportunity to begin to grow again.