Giant gypsum crystals grew from a water solution that filled a limestone cave located about 244 m (800 ft) underground in Mexico's state of Chihuahua. In some passageways, the bladelike crystals form a veritable corridor of swords. Miners extending a tunnel in Maravilla Silver Mine accidentally discovered this cave of swords in the early 1900s.
Fed by a mineral-rich solution that seeped through rock, this specimen grew from the wall of a cave. The "ram's horns" curved as some crystal strands grew faster than others.
The chemical composition of gypsum is CaSO4.2H2O. Pure gypsum is a whitish clear mineral. The yellowish cast of this specimen is caused by sulfur impurities in the crystals.
These chisel-shaped crystals grew in a cavity in limestone filled with water rich in dissolved minerals. Large deposits of gypsum are mined to make plaster of Paris, wallboard, alabaster carvings, and stucco.
