sedimentary
Alabaster
Gypsum (Calcium Sulfate Dihydrate, CaSO4·2H2O)
Mohs hardness of 2, white to translucent color, pearly to earthy luster, monoclinic crystal system, good cleavage, specific gravity of 2.3
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Physical properties
Mohs hardness of 2, white to translucent color, pearly to earthy luster, monoclinic crystal system, good cleavage, specific gravity of 2.3
Formation & geological history
Formed as an evaporite deposit from the precipitation of calcium sulfate from concentrated marine or lake waters, typically in arid environments over geological timescales.
Uses & applications
Used in sculpture, ornamental carvings, interior decoration, plaster of Paris production, and educational geology kits.
Geological facts
Alabaster has been used by humans for millennia, notably by the ancient Egyptians for carved jars and statues due to its softness and translucency.
Field identification & locations
Easily identified by its very soft nature (can be scratched easily with a fingernail) and its fine-grained, massive white appearance. Commonly found in sedimentary rock sequences worldwide.
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