1. (Science: chemical) a compact variety or sulphate of lime, or gypsum, of fine texture, and usually white and translucent, but sometimes yellow, red, or gray. It is carved into vases, mantel ornaments, etc. A hard, compact variety of carbonate of lime, somewhat translucent, or of banded shades of colour; stalagmite. The name is used in this sense by Pliny. It is sometimes distinguished as oriental alabaster.