Mexico’s Giant Crystal Cave Is Beautiful But Deadly ... the ground water and it became saturated with minerals, including large quantities of gypsum. The hollow space of the cave was filled ...

The Cave of Crystals is an underground cavern filled with tree-size gypsum crystals, including some of the largest natural ...

Deep below the surface of an isolated mountain range in Mexico ... in these caves, rich with sulfur from the adjacent metal deposits, began dissolving the limestone walls, releasing large ...