© Speleoresearch & Films / Oscar Necoechea.

Spectacular freely developed gypsum crystals up to 12 m, possibly the largest in the world

Cave of the Crystals or Giant Crystal Cave (Spanish: Cueva de los Cristales) is a cave connected to the Naica Mine 300 metres (980 ft) below the surface in Naica, Chihuahua, Mexico.

The main chamber contains giant selenite crystals (gypsum, CaSO4·2 H2O), some of the largest natural crystals ever found.

The cave’s largest crystal found to date is 11 m (36 ft) in length, 4 m (13 ft) in diameter and 55 tons in weight.

The cave is extremely hot with air temperatures reaching up to 58 °C (136 °F) with 90 to 99 percent humidity. The cave is relatively unexplored due to these factors. Without proper protection people can only endure approximately ten minutes of exposure at a time.

Giant gypsum crystals up to 12 m in the lower levels of Naica mine

© Speleoresearch & Films / Oscar Necoechea.

The Naica gypsum crystals in a nutshell:

  • Mineralogy: Gypsum, possibly some sulfide minerals
  • Crystal Size: mostly freestanding prismatic crystals up to 12 m
  • Geology & Origin: Possibly hydrothermal replacement of limestone by sulphuric acids, more research is certainly warranted
  • Current status: Active mine, access to upper crystal caves for tourists possible, access to lower crystal caves remain restricted
  • Remarks: Spectacular freely developed (!) gypsum crystals up to 12 m, possibly the largest in the world

Subject Related Links:

http://www.naica.com.mx/english/index.htm