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Gypsum

Gypsum

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.

Gypsum

Gypsum

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.

Gypsum

Gypsum

Gypsum

Gypsum

Gypsum

Gypsum

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.

Gypsum (variety: Selenite)

Gypsum (variety: Selenite)

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.

Gypsum Flower

Gypsum Flower

The curling "horns" on this specimen result from some of the crystals in the strand growing faster than others.


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