alabaster, fine-grained, massive, translucent variety of gypsum, a hydrous calcium sulfate. It is pure white or streaked with reddish brown. Alabaster, like all other forms of gypsum, forms by the evaporation of bedded deposits that are precipitated mainly from evaporating seawater. It is soft enough to be scratched with a fingernail and hence it is easily broken, soiled, and weathered. Because of its softness, alabaster is often carved for statuary and other decorative purposes. It is quarried in England and also in Italy. Vases and statuettes of Italian alabaster are sold as "Florentine marbles." The term "Oriental alabaster" is a misnomer and actually refers to marble, a calcium carbonate; whereas gypsum is a calcium sulfate. Important sources of alabaster are Algeria, Egypt, Iran, and Mexico (from which it is exported under the name Mexican onyx); in the United States there are important sources in Utah and Arizona. Oriental alabaster (marble) was extensively used by the Egyptians in sarcophagi, in the linings of tombs, in the walls and ceilings of temples, and in vases and sacrificial vessels. The Romans worked the Algerian and Egyptian quarries and used the stone for similar purposes. In modern times it was used by Muhammad Ali for his mosque in Cairo. The French make extensive use of alabaster in interior decoration.

Alabaster, William, 1567-1640, English theologian and poet. Although he wrote two epic poems in Latin, he is remembered for his theological studies, including Spiraculum Tubarum (1633). Alabaster converted to Roman Catholicism in Spain in 1597 and was imprisoned on his return to England in 1598. He reconverted to Protestantism and was chaplain to James I.

Fine-grained gypsum that has been used for centuries for statuary, carvings, and other ornaments. It normally is snow-white and translucent but can be artificially dyed; it may be made opaque and similar in appearance to marble by heat treatment. Florence, Livorno, Milan, and Berlin are important centres of the alabaster trade. The alabaster of the ancients was a brown or yellow onyx marble.

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