Naica Mine

I have gotten a e-mail recently from one of my readers, Eileen. She was nice enough to send me a wonderful powerpoint slide show on the crystal caves discovered in Chihuahua Mexico. Here is what I found out about it :

The Naica Mine of Chihuahua, Mexico, is a working mine that is known for its extraordinary selenite crystals. Naica is a lead, zinc and silver mine in which large voids have been found, containing crystals of selenite (gypsum) the cave contains some of the largest natural crystals ever found: translucent gypsum beams measuring up to 36 feet (11 meters) long and weighing up to 55 tons. Buried a thousand feet (300 meters) below Naica mountain in the Chihuahuan Desert, the cave was discovered by two miners excavating a new tunnel for the Industrias Peñoles company in 2000.

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”. From the discovery until about 1900, the primary interest was silver and gold. Around 1900 large-scale mining began as zinc and lead became more valuable. During the Mexican Revolution the mine was producing a great deal of wealth. Revolutionary troops entered the town and demanded money from the owners. One of them was assassinated when he refused to pay, causing the mine to shut down from 1911 to 1922.

In April 2000, brothers Juan and Pedro Sanchez were drilling a new tunnel when they made a truly spectacular discovery. While Naica miners are accustomed to finding crystals, Juan and Pedro were absolutely amazed by the cavern that they found. The brothers immediately informed the engineer in charge, Roberto Gonzalez. Ing. Gonzalez realized that they had discovered a natural treasure and quickly rerouted the tunnel. During this phase some damage was done as several miners tried to remove pieces of the mega-crystals, so the mining company soon installed an iron door to protect the find. Later, one of the workers, with the intention of stealing crystals, managed to get in through a narrow hole. He tried to take some plastic bags filled with fresh air inside, but the strategy didn’t work. He lost consciousness and later was found thoroughly baked.

The mining company was afraid to tunnel through the Naica fault for fear of flooding the entire mine. In April 2000, the company became confident that the water table on the other side of the fault had been lowered sufficiently to drill. When they did this, it is almost as if a magical veil of reality was breached and an entirely new world was discovered. Two caverns filled with the Earth’s largest crystals were immediately revealed. More discoveries are expected to be made in this magical kingdom of intense natural beauty.

To learn how the crystals grew to such gigantic sizes, García-Ruiz studied tiny pockets of fluid trapped inside.
The crystals, he said, thrived because they were submerged in mineral-rich water with a very narrow, stable temperature range—around 136 degrees Fahrenheit (58 degrees Celsius). At this temperature the mineral anhydrite, which was abundant in the water, dissolved into gypsum, a soft mineral that can take the form of the crystals in the Naica cave.

Selenite is one of the most beautiful varieties of gypsum, being a mineral composed of calcium sulfate hydrate (CaSO4•2H2O) it quite often forms compact and lucid laminate aggregations. It sometimes presents itself in the shape of giant crystals with perfect laminate exfoliation, and amazing reflectivity. The Naica caves are the greatest expression of magnitude and beauty in the world.

When photographing these unique natural structures it is almost impossible to get any sense of scale. This is a geode full of spectacular crystals as tall as pine trees, and in some cases greater in circumference. They have formed beautiful crystals that are a translucent gold and silver in color, and come in many incredible forms and shapes. Some of the largest are essentially columnar in shape and stand thirty to fifty feet high and three to four feet in diameter. Many of the smaller examples are four to six feet in circumference, have many incredible geometrical shapes, and probably weigh in excess of ten tons. While some of the crystals are attached to the ceiling walls and floors of the cave as might be expected, some exist in great masses of spikes and almost float in air.

The crystal cavern was discovered within the same limestone body that hosts the silver-zinc-lead ore bodies exploited by the mine. The cavern was probably dissolved by the same hydrothermal fluids that deposited the metals with the gypsum being crystallized during the waning stages of mineralization. The crystals probably grew relatively quickly to their immense size within a completely liquid-filled cavern.

It is almost impossible to obtain clear photographs, because of the extreme ambient environment. These crystals are probably stable, as the temperature in the cave is over 150 degrees Fahrenheit with 100% humidity. In other words, these structures are enveloped in steam. A human can only function in this environment for six to ten minutes before severe loss of mental functions occurs.

Selenite, the gypsum crystal, named after the Greek goddess of the moon due to its soft white light, is said to have many metaphysical and healing benefits. Selenite powder has been used cosmetically for thousands of years to enhance one’s natural beauty. It is believed that this crystal assists with mental focus, growth, luck, immunity, and soothes the emotions. It is unquestionably magical that the cool white rays of moonlight can originate deep underground in a black chamber that is, at least in my perception, white hot.
I found most of the material from the following sites :

Canyons Worldwide, That Crystal Site, Wikipedia, Crystal Links, Naica and National Geographic.

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