We have two types of Alabaster – Spanish or Italian Alabaster and US Alabaster 

In ancient times Alabaster was often used to create carvings dedicated to the gods in cults and religious worship. And,due to the translucent qualities of alabaster,  it was also cut into thin slices and used as windows in medieval churches.

Alabaster has some of the most beautiful translucent and opague qualities of any natural stone –  and hence is one of the most prized of carving stones.

Alabaster Physical Characteristics & Composition

Alabaster is a name applied to a variation of two distinct minerals –  gypsum (a hydrous sulphate of calcium) and calcite (a carbonate of calcium). The chemical composition of alabaster stone is the same as that of gypsum (calcium sulphate dihydrate).

Gypsum is a salt formed by precipitation in lakes and large bodies of water transformed by evaporation (evaporite basins). As water evaporates, a saturation point is reached for the different salts to precipitate. The accumulation of these gypsum crystals at the bottom of the lake will eventually lead to the creation of alabaster.

The two kinds of alabaster have different hardness levels. The gypsum alabaster is softer and can be scratched with a fingernail (Mohs hardness 1.5 to 2). The calcite alabaster is harder (Mohs hardness 3), although you can scratch it with a knife.