Crystal Caves - The Naica Mine of Chihuahua, Mexico

It's "the Sistine Chapel of crystals," says Juan Manuel García- Ruiz. The geologist announced this week that he and a team of researchers have unlocked the mystery of just how the minerals in Mexico's Cueva de los Cristales (Cave of Crystals) achieved their monumental forms.

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 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.

"It's a natural marvel," said García-Ruiz, of the University of Granada in Spain.

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.

The new findings appear in the April issue of the journal Geology.

(Related" "Photo in the News: Giant Crystal-Filled Cave Discovered in California" [September 26, 2006].)

Volcanic Activity

The mining complex in Naica contains some of the world's largest deposits of silver, zinc, and lead.

In 1910 miners discovered another spectacular cavern beneath Naica. Its walls studded with crystal "daggers," the Cave of Swords is closer to the surface, at a depth of nearly 400 feet (120 meters).

While there are more crystals in the upper cave, they are far smaller, typically about a yard (a meter) long.

Nearly the Size of a Basketball Court

The Cave of Crystals is a horseshoe-shaped cavity in limestone rock about 30 feet (10 meters) wide and 90 feet (30 meters) long.

Its floor is covered in crystalline, perfectly faceted blocks. The huge crystal beams jut out from both the blocks and the floor.

"There is no other place on the planet where the mineral world reveals itself in such beauty," García-Ruiz said.

Volcanic activity that began about 26 million years ago created Naica mountain and filled it with high-temperature anhydrite, which is the anhydrous—lacking water—form of gypsum.

Anhydrite is stable above 136 degrees Fahrenheit (58 degrees Celsius). Below that temperature gypsum is the stable form.

When magma underneath the mountain cooled and the temperature dropped below 58 degrees Celsius, the anhydrite began to dissolve. The anhydrite slowly enriched the waters with sulfate and calcium molecules, which for millions of years have been deposited in the caves in the form of huge selenite gypsum crystals.

"There is no limit to the size a crystal can reach," García-Ruiz said.

But, he said, for the Cave of Crystals to have grown such gigantic crystals, it must have been kept just below the anhydrite-gypsum transition temperature for many hundreds of thousands of years.

In the upper cave, by contrast, this transition temperature may have fallen much more rapidly, leading to the formation of smaller crystals.

To Reflood or Not to Reflood

While the chance of this set of conditions occurring on other places in the world is remote, García-Ruiz expects that there are other caves and caverns at Naica containing similarly large crystals.

"The caves containing larger crystals will be located in deeper levels with temperatures closer to, but no higher than, 58 degrees Celsius," he said.

He has recommended to the mining company that the caves should be preserved.

The only reason humans can get into the caves today, however, is because the mining company's pumping operations keep them clear of water. If the pumping is stopped, the caves will again be submerged and the crystals will start growing again, García-Ruiz said.

So what happens if—or when—the mine is closed?

"That's an interesting question," García-Ruiz said.

"Should we continue to pump water to keep the cave available so future generations may admire the crystals? Or should we stop pumping and return the scenario to the natural origin, allowing the crystals to regrow?"

Found Here: http://news.nationalgeographic.com/news/2007/04/070406-giant-crystals_2.html

Naica is a paradox.

Contrary to many underground natural wonders, Naica is a surprising find. 300 meters deep, it has no natural openings to the surface, so it would have never been found if there hadn’t been the Industrias Peñoles mining complex operating there. Some caves require days of expeditions to reach, and film crews have to live in tents and cook their own food. Naica is the opposite, an improbable “film studio” environment. The cave is accessed by simply driving directly from our production office down a tunnel. Down there, we have plenty of electricity and establish a base camp with lights, computers, food, drinks, miscellaneous equipment, etc. Once the day is over, we drive back up, debrief, drive back to our hotel, eat, shower and sleep in a modern room with wireless Internet access and cable TV. That’s the easy part.

There are two doors between the base camp and the giant crystals.

What lies beyond those doors is another story. The base camp is tropical-like, warm and humid, an uncomfortable set in a stone-carved 100-meter long corridor. The closest you get to the 1st door, the warmer it gets. Open the metal door and you instantly feel a draft of noticeably warmer air. Making your way through another corridor leading to two stone-carved steps, it gets much warmer. You go up the steps, not even three feet higher, but you suddenly feel even more oppressive heat and humidity, it’s hard to breathe and you sweat instantly. You can see the giant crystals stretch in all directions beyond the transparent plastic door. Standing there you tell yourself : “This isn’t too bad… Just like a sauna with obstacles.”

Then you open the plastic door…

A burning wall hits you and you are shocked. Until then you haven’t really experienced Naica. Now you are in a humid hell and your feel your entire body sending you messages: “Get out of there NOW! You are in mortal danger.”

No joke. From that moment on, you are.

But you’re safe for now because you just walked in, full of your precious bodily fluids and electrolytes. Climbing over big crystals, you make your way deeper in the cave, giving 100% of your attention to breathing slowly and not falling on the razor-sharp crystals, you then make a stop and raise your head.

You will remember this moment until your last breath.

The first sight of the giant crystals stretching in all directions is impossible to describe. You are in awe, and yet you have a lot of difficulty appreciating it because your entire body is fighting a losing battle against the elements. The Humidex factor of the combined heat and humidity of Los Cristales cave is double the death threshold. Unprotected you can stay 10 to 15 minutes, after that your body is essentially a walking time bomb ready to overheat and die.

But someone is watching over you.

A voice on the walkie-talkie tells you it’s time to go. You reply back and make your way to the exit. You were never really in danger, because the Naica Project team, who have been filming at Naica for almost 4 years know how to keep you safe.

Naica is one of the most remote, beautiful, dangerous place I’ve ever visited, yet it’s surprisingly easy to access, breathtakingly hard to appreciate and, if you don’t go too far in, it’s very safe.

Read more: http://channel.nationalgeographic.com/episode/into-the-lost-crystal-caves-4636/Overview#tab-mortal-danger#ixzz1DFopklf3

The Naica Mine of Chihuahua, Mexico, is a working mine that is known for its extraordinary crystals. Naica is a lead, zinc and silver mine in which large voids have been found, containing crystals of selenite (gypsum) as large as 4 feet in diameter and 50 feet long. 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". Perhaps here in the small canyon there was a grove of trees tucked away by a small canyon spring.

From that discovery, until around 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.

Just before the mine was closed, the famous Cave of Swords was discovered at a depth of 400 feet. Due to the incredible crystals, it was decided to try to preserve this cave. While many of the crystals have been collected, this is still a fascinating cave to visit. In one part there are so many crystals on one of the walls, they appear to be like an underwater reef moving in a gentle undulating motion in an ocean current.

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.

When entering the cave our group is issued helmets, lanterns, rubber boots, and gloves. One must then be driven by truck into the main mining tunnel called Rampa Sn. Francisco. While the vertical drop is approximately 1000 feet, the drive is almost a half mile long. The heat steadily increases and women have been observed to begin "glowing". The truck stops in front of a concrete wall with a steel door. The intense heat can prevent brain functioning.

At the end of the tunnel there are three or four steps into the aperture of the cavern itself. It is in this short tunnel. In this short distance the temperature and humidity goes from being uncomfortably warm to literally a blast furnace.

Momentarily, the penetrating heat is forgotten as the crystals pop into view on the other side of the "Eye of the Queen". The entire panorama is now lighted and the cavern has a depth and impressive cathedral-like appearance that was not visible on earlier trips with just our headlamps.

When inside the great cathedral of crystals, the pressure of intense heat create a gamut of emotions and perhaps hallucinations. One can only remain for a short period of time.

Geologists report that these natural crystal formations are incredibly complex, yet so simple. They have a magical or metaphysical personality independent of their chemical structures. There is a magma chamber two to three miles below the mountain and that heat from this compressed lava travels through the faults up into the area of the mine. Super heated fluids carry the minerals the miners are seeking as well as form the crystals. The mine is ventilated; otherwise, it could not be worked. Some parts, however, are not air-conditioned, such as the Cave of the Crystals, and there you feel the heat from the magma deep below. The fluids travel along the Naica fault, enter voids in the bedrock, and then form entirely natural structures that are not easily explained scientifically.

In April 2000, the mining 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.

Selenite, the gypsum crystal, named after the Greek goddess of the moon, Selene, 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.

Found Here: http://www.crystalinks.com/mexicocrystals.html