I Love Geology
Cave of the Crystal Giants...

The Naica mine in Chihuahua, Mexico is best known for its extraordinary selenite crystals. They are some of the largest ever discovered - reaching 4 feet (1.2 meters) in diameter and 50 feet (15.2 meters) in length.
The magma beneath the cave makes it unbearably hot and humid. As a result, the cave remains largely untouched.

The Naica mine in Chihuahua, Mexico is best known for its extraordinary selenite crystals. They are some of the largest ever discovered - reaching 4 feet (1.2 meters) in diameter and 50 feet (15.2 meters) in length.
The magma beneath the cave makes it unbearably hot and humid. As a result, the cave remains largely untouched.