Cave of the crystals – naica mine

Cave of the Crystals or Giant Crystal Cave

Naica Mines

Cave of the Crystals, also known as Giant Crystal Cave (Spanish Cueva de Los Cristales), is an underground cave that connects to the Naica Mine at 300m (980 feet), in Naica Chihuahua.

It contains the largest known crystal and is the most extensive crystal mine we have ever found.

The main crystal chamber is home to giant selenite crystals (gypsum and CaSO4* 2H2O), some of the most impressive natural crystals. The largest crystal discovered in Cave is 12 m (39 feet) long, 4m (13 feet) wide and 55 tons in weight.

It was very hot in the Cave’s time, with temperatures of up to 58 degrees Celsius (136 degrees Fahrenheit) and a high humidity level of between 90 and 99 per cent. These factors make the Cave relatively challenging to explore. People can only survive approximately ten minutes without proper protection and equipment.

Cave of the crystals – naica mine

Juan and Pedro Sanchez, brothers, discovered the Crystal Cave while drilling in the mine. The mine had been flooded by October 2015. As a result, the cavern was filled with water rich in minerals and nutrients that would allow the crystals to grow.

These caverns are being investigated by the Naica Project, a group of scientists.

Formation of crystals in The Cave of the Crystals

Naica is located on an ancient fault line, just 3-5 km (2-3 mi) below Cave. The magma heated groundwater and liquid, which were then saturated with sulfide (S2) ions. The cool, oxygenated water surface contacted the mineral saturated, heated, & warm water. Still, they didn’t mix because of the differences in their densities.

The heated water was slowly heated, and the oxygen diffused or dissolved into it. This oxidised the sulfides S2- into sulfates SO42-, which precipitated as anhydrite CaSO4. The Cave’s temperature dropped below 56 degrees Celsius, and the crystals of hydrothermal and sedimentary hydrite were dissolved. Gypsum (CaSO4* 2H2O crystals) was created.

The massive crystals formed today by the hydrated sulfate-gypsum crystallised at a very slow rate for a minimum of 500,000 years.

Cave of the crystals – naica mine

Discover the Cave of Crystal at Naica Mine

Miners discovered the Cave of Swords in 1910. It is located 120 m (390 ft) below the Cave of the Crystals and has spectacular, shorter (1-meter (3 ft 3) in) crystals. The possibility that the transition temperatures have dropped faster at this elevation may have led to the end of crystal growth.

Miners discovered the Giant Crystal Cave while digging through the Naica fault to dig a replacement tunnel for Industrias Penoles, a mining company located in Naica Mexico. They were concerned that the fault would flood their Naica mine. There are significant deposits of silver, zinc and lead in the Naica mining complex & caves.


The Cave of Crystals could be described as a horseshoe-shaped cave in limestone. The floor is made up of perfectly faceted, layered crystalline blocks. The floor is adorned with massive crystal beams that rise from the blocks. Crystals can deteriorate in the air. The Naica Project tried to document these crystals before they became more visually distorted.

In 2000, two other caves or caverns smaller were discovered. The Queen’s Eye Cave was also discovered, as well as Candles Cave. A third chamber was also found during a drilling operation in 2009. Ice Palace is 150m (490 feet) deep. It isn’t flooded. However, its crystal formations are smaller with fine, thread-like crystals and small “cauliflowers”.


Exploration and scientific research

Paolo Forti (Italy), a specialist in cave minerals and crystallographer at the University of Bologna, led a scientific team that explored the subsurface detail.

They developed refrigerated suits, cold breathing systems and Tolomea suit to survive in extreme temperature and humidity conditions.

A special caving outfit or pants was fitted with a mattress or cover of refrigerating tube covers placed all over the body and connected to a backpack that weighed around twenty kilograms (44lb) and containing a reservoir of cold water & ice. The right conditions were maintained for about half an hour by the cooling effect of melting ice.

Apart from mineralogical and crystallographic research, biogeochemical and microbial characterisations of the giant gypsum crystals were also done. Stein-Erik Lauritzen (the University of Bergen in Norway) performed uranium-thorium dating, which allowed the determination of the crystals’ exact age of approximately 500,000 years.

Cave of the crystals – naica mine

A. E. S. Van Driessche led a team that measured the expansion rates for these giant gypsum crystals with the current water & moisture from the Naica. The growth rate measured by the Naica was 1.4 +-0.2 x 10-5nm/s. This is the slowest rate of crystal growth. This rate would have required approximately 1,000,000 years for the largest crystals to reach their current size.

Penelope Boston (New Mexico Institute of Mining and Technology), a speleologist and geomicrobiologist specialising in extremophiles achieved sterile sampling of gypsum drillcores through small boreholes within large crystals. This was done under clean conditions.

It was intended to determine whether fluid or solid inclusions in the calcium sulfate matrices may have been used to encapsulate ancient or early-life bacteria. The solid inclusions are mainly composed of magnesium and iron oxide, but there is no organic matter.

Researchers, including Dr Boston, presented the discovery of bacteria in inclusions in crystals at the American Association for the Advancement of Science (AAAS) 2017 meeting.


The researchers used sterile methods to extract the organisms and then reanimate them. These organisms are not closely related to any of the genetic databases. The researchers later reported that the microbes could be as old as 50,000 years.

Other research included palynology (pollen studies), geochemistry, and hydrogeology, which helped determine the physical conditions in the Cave of Crystals.

The Cave of Crystals Closure

The Crystal Cave was featured on Discovery Channel’s Naica: Beyond The Crystal Cave, February 2011. It was previously featured in the History Channel’s episode “Depths of Destruction”, part of the second season of Life After People.

Although exploration has confirmed the existence of other chambers, further research would have required significant crystal removal. The Cave’s accessibility is dependent on the mine’s water pumps. After mining operations ended, the caves were allowed by the government to be refilled in October 2015.

Researchers might be allowed to return to their research if the company opens another entrance. This is in accordance with a February 2019 report.



Juan Manuel Garcia Ruiz, a geologist, calls it “the Sistine Chapel for crystals”, but Superman would call it his home.

How come crystals can reach such large sizes?

In the new issue Geology, Garcia-Ruiz reports that crystals have thrived in the Cave’s unique and stable natural environment over millennia. The Cave was filled with mineral-rich water, which drove crystal growth.


Modern mining and drilling revealed the natural crystal wonder. Water was pumped out of the cavern or Cave measuring 30 by 90 feet (10 by 30 meters) near Delicias in 2000. Garcia-Ruiz now advises the company to protect the caves.

Garcia-Ruiz stated, “There is no other place on earth where the mineral world can be revealed in such beauty.”

Giant Crystal Cave is filled with Light.


says Juan Manuel Garcia – Ruiz.

In the following week, the geologist revealed that he and a group of researchers had solved the mystery of how the massive minerals found in Mexico’s Cueva de Los Cristales (Cave of Crystals) got their extraordinary forms.


Two miners found the Cave, located one thousand feet (390 meters) below Naica Mountain in the Chihuahuan Desert. They were digging a new tunnel for Industrias Penoles in 2000.

The Cave is home to many of the finest natural crystals known, including translucent gypsum beams that measure up to 36 feet in length and weigh 55 tonnes.

Garcia-Ruiz looked at tiny pockets of fluid and water inside to discover how these massive crystals developed.

He stated that crystals thrived in mineral-rich water at a stable temperature of 136° Fahrenheit (or 58° Celsius).


This temperature allowed the mineral anhydrite to dissolve into gypsum. Gypsum is a soft mineral that will form the crystals in the Naica cave.

Naica’s mining complex contains some of the largest world-class lead, zinc, silver, and zinc deposits.

1910 miners discovered another impressive cavern or Cave below Naica.

The Cave of Swords, with its walls studded in crystal “daggers” or knives, is closer to the surface at a depth of almost 400 feet (120 m).


Although there are more crystals in the upper Cave than you might think, they are usually only a few yards (a meter).

Crystals’ Cave is horseshoe-shaped in the limestone rock, approximately 30 feet (10 m) wide by 90 feet (30 m) long.

The floor is covered in perfectly faceted, crystallised blocks and layers. Both the floors and the blocks are adorned with large crystal beams.

“There’s no other place on earth where the beauty of the mineral world is as beautiful as it is here.”

Garcia-Ruiz said.

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