Alabaster

Alabaster is a soft, fine-grained, translucent stone traditionally used for carving. The term covers two different materials: the more common gypsum alabaster (hydrated calcium sulfate) and the harder calcite alabaster (calcium carbonate), sometimes called oriental or Egyptian alabaster.

Its smooth texture, softness and gentle translucency, which lets light glow through thin sections, have made it a favorite of sculptors since antiquity. It is usually white to cream, sometimes banded, veined or lightly tinted by impurities.

Because it is so soft and water-sensitive (especially the gypsum type), alabaster is used for indoor and decorative objects rather than durable outdoor stone.

Gypsum alabaster forms as a sedimentary evaporite mineral, precipitating when bodies of salt water or saline lakes evaporate and concentrate calcium sulfate, which crystallizes into massive fine-grained gypsum beds and nodules.

Calcite alabaster, by contrast, forms as a chemical deposit from carbonate-rich waters, typically as banded travertine or stalagmitic material in caves and around springs. Famous alabaster sources include Volterra in Italy and Spain (gypsum alabaster) and Egypt (calcite alabaster). Both types occur where the right chemistry and slow precipitation allowed fine, compact crystalline masses to develop.

Alabaster is recognized by its softness, smooth feel, fine even grain, and waxy translucency. Gypsum alabaster is so soft it can be scratched with a fingernail (hardness 2), which distinguishes it from marble and calcite alabaster.

To tell the two apart, apply dilute acid: calcite alabaster fizzes, while gypsum alabaster does not. Alabaster is often confused with marble, but marble is much harder (around 3 to 4 and clearly not fingernail-scratchable) and more crystalline. The combination of softness, translucency and fine texture, plus the acid test, reliably identifies and subdivides alabaster.

Alabaster has been carved into sculptures, vases, lamps, window panes and ornaments for thousands of years, valued for its workability and the soft glow of light through it. The Egyptians made vessels and canopic jars from calcite alabaster, and Renaissance and later European artists carved gypsum alabaster figures and reliefs.

Today it is still used for decorative carvings, lampshades, tableware and interior architectural details. Because gypsum alabaster is soft and dissolves slowly in water, finished pieces are kept indoors and handled with care. It is not used as a gemstone but is a celebrated ornamental and lapidary material.