For its pale translucence, this crystal form of the mineral gypsum is known as selenite, named after Selene, the Greek goddess of the moon. "Under perfect conditions," says Roberto Villasuso ...

The gypsum crystals in the Naica Mine are the largest natural crystals ever found. They can grow up to 36 feet (11 meters) long and weigh up to 55 tons. The cave is located at a depth of 2,300 ...