Naica Mine
CountryMexico
RegionChihuahua
Year Opened1828
Size/Depth300 m deep
MineralLead/Silver
About Naica Mine
Contains the Cave of the Crystals, with selenite crystals up to 12 m long and 4 m wide. The cave temperature is 58C with 99% humidity - lethal after 10 minutes. The crystals grew over 500,000 years. The cave was flooded again in 2015 to preserve them.