Alabaster

Alabaster (sometimes called satin spar) is a name applied to varieties of two distinct minerals: gypsum (a hydrous sulfate of calcium) and the calcite (a carbonate of calcium). The former is the alabaster of the present day; the latter is generally the alabaster of the ancients.

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The two kinds are readily distinguished from each other by their relative hardnesses. The gypsum kind is so soft as to be readily scratched by a finger-nail (hardness 1.5 to 2), while the calcite kind is too hard to be scratched in this way (hardness 3), though it does yield readily to a knife. Moreover, the calcite alabaster, being a carbonate, effervesces on being touched with hydrochloric acid, whereas the gypsum alabaster, when so treated, remains practically unaffected.

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Mineral: This article is about minerals in the geologic sense; for nutrient minerals see dietary mineral; for the band see Mineral (band)....

Gypsum: Gypsum is a very soft mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO4·2H2O....

Hydrous: REDIRECT Hydrate...

Alabaster related Images and Photos (experimental)

Alabaster Nudibranch Barkley Sound Canada	Alabaster Box and Bronze and Silver Seal Cylinders of King Mentuhotep Middle Kingdom	A Babylonian Alabaster Statue of Ishtar the Goddess of Love Dating from 350 B.C.	Funerary Stela from Yemen (Alabaster)
Statuette of Astarte 3rd-2nd Century BC (Alabaster)