Content by courtesy of: The Giant Crystal Project
Reproduction of text and photos prohibited without permission of author.
Permission to republish these information on the Giant Crystal Project Site was kindly given by Dave Tucker of Datamine / UK
This article is based on a report in a Mexican newspaper. It has been translated into English and edited by two of the staff at the Peņoles Naica mine who have also provided some additional facts and figures. Many thanks to :
Naica Crystal Caves
Deep below the surface of an isolated mountain range in Mexico sit two rooms of splendor: translucent crystals the length and girth of mature pine trees lie pitched atop one another, as though moonbeams suddenly took on weight and substance. In April 2000, brothers Eloy and Javier Delgado found what experts believe are the world's largest freestanding crystals while blasting a new exploration tunnel deep in the silver, lead and zinc Naica Mine of southern Chihuahua. After discovering a small opening about 300 metres down, Eloy squirmed inside and found an 8 metre cavern full of immense crystals. One and a half months later, another team of Naica miners happened upon an even larger cavern adjacent to the first one.Geologists conjecture that a chamber of magma, or superheated molten rock, lying two to three miles underneath the mountain forced mineral-rich fluids upward through a fault into openings in the limestone bedrock near the surface. Over a period of time, maybe more than 30 million years, this hydrothermal liquid deposited sulphides rich in silver, lead and zinc on the limestone bedrock. These metals have been mined here since prospectors discovered the deposits in 1794 in a small range of hills south of Chihuahua City. In addition, the hydrothermal fluids dissolved gypsum, the same material used in wallboard and plaster of paris, located in the bedrock. Hot, mineral-rich solutions gave birth to these giant selenite crystals.
In addition to 1 metre diameter columns 15 meters in length, the cavern contains row upon row of shark-teeth-shaped formations up to 1 metre high, which are positioned at odd angles throughout the cave. Until April 2000, mining officials had restricted exploration on one side of the fault out of concern that any new tunnel might lead to flooding of the rest of the mine. Only after the water table had dropped sufficiently did they authorize the tunnel that led to the Sanchez brothers' astonishing discovery.
Previously, the world's largest examples of selenite crystals came from a nearby cavern discovered in 1910 within the same Naica cave complex. Several examples from the Cave of Swords are exhibited at the Janet Annenberg Hooker Hall of Geology, Gems, and Minerals at the Smithsonian's National Museum of Natural History.
Giant Selenite crystals in the Naica mine, Mexico
Some additional facts and figures: