Mineral Species: Gypsum

Chemical Formula: CaSO4.2H2O

Chemical Name: Hydrous Calcium Sulphate

Mineral Class: Sulphate

Mineral Notes: Gypsum is the commonest sulfate. It is a major rock forming mineral that forms massive beds, usually from precipitation out of highly saturated waters. Since it forms easily from saline water, gypsum may have many inclusions of other minerals and even trapped bubbles of air and water. The Ramshorn variety is characterised by elongated crystals forming long curved clusters, resembling animal horns, hence the name.

Description: This is a very characteristic specimen consisting of white Gypsym forming an aggregate which curves around and then splits into two branches. Close examination shows the indivisual crystals, which are long and columnar. A very notable feature of the specimen is its silky luster.

Location: Durango, Mexico.