The formation of the Cave of Crystals is a testament to the incredible forces of nature. The cave, made of limestone, sits ...

The cavern, which is made of limestone, sits above a magma reservoir buried three to five kilometres (two to three miles) beneath Naica, and is also on a faultline. Its crystals were formed when ...

began dissolving the limestone walls, releasing large quantities of calcium. This calcium, in turn, combined with the sulfur to form crystals on a scale never before seen by humans. "You can hold ...