Last chance to see: Video of Mexico's Naica Cave of Crystals (Previously, and previously.) [more inside]
posted by Hardcore Poser on Jan 20, 2010 - 20 comments

Crystal Palace. "Cavers in Mexico confront extreme conditions and find extraordinary beauty." (Previously.)
posted by homunculus on Oct 22, 2008 - 34 comments

The gypsum crystals in the Cave of Crystals at the Naica mine in Chihuahua, Mexico, are some of the largest and most spectacular in the world. [Last link is a .wmv]
posted by dersins on Aug 3, 2007 - 18 comments

50 foot long single spar crystals found in a Mexican cave 1,000 feet below the surface! Smithsonian has links to other related sites. This one has pictues. More pictures can be found in the April 2002 print issue of Smithsonian.
posted by onhazier on Mar 26, 2002 - 11 comments