Chihuahua, northern Mexico, under the ground exists a crystal wonderland. During the year 2000 an accidental discovery was unveiled world-wide. I guess that the people who came into the NAICA crystal cave were captivated by the shine, transparency and huge size of the geological formations.
Imagine several caves located between 120 and 300 meters below the ground that each one of them shelters magnificence selenite crystals of a highest purity that reaches lengths of up to 11 m, twenty times bigger than other known crystals in the world.
However, what process allows the formation of such crystals? NAICA caves form part of a phreatic system of thermal waters. These macro crystals were formed under sulphide saturated waters of 52ºC came in contact with oxygen rich cold waters. As a result, oxygen diffused into the lower layer, oxydation sulphide ions to sulphate. These singular conditions prevailed for hundreds of thousands of years until today.
Although the cave system is very extensive, only four caves are well described:
Sword’s cave: located under 120 m, this cave was discovered in 1910. It is a 87 m cavity along, completely covered by crystals up to 2 m. A geological study revealed that the crystals are of a complex composition, rich in fossilized biological forms such pollen. That implies a great interest for defining the micro climate in the area at the time of cave’s formation.
Candle’s cave: is the latest founded cave. About 80 m, consists of two main large rooms in two levels. It is unique for the small and thin speleothems (the candles). This formations have only 20 years and are unique in the world.
Queen’s eye cave: is a geode type cave about 8 m in diameter lined by white translucent and transparent crystals as a big eye looking at the intruders that come into in 2000.
Crystal’s cave: discovered in 2000, under 50ºC of temperatures and 100% of humidity. Contains 11 m selenite mega crystals. The walls and the floor are sprinkled with blocky single crystals.