The American Heritage® Dictionary of the English Language, 4th Edition
n. A white, red-brown, orange, or light blue principal strontium ore, essentially strontium sulfate, SrSO4, found in sedimentary rock. Also called celestine.
n. A colourless, orange or blue mineral, strontium sulfate, SrSO4, that is an ore of strontium and constitutes the skeletons of Acantharea.
The Century Dictionary and Cyclopedia
n. In mineralogy, native strontium sulphate.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. a mineral consisting of strontium sulphate
Word Usage
"Uniquely, the spiny skeletons and cyst shells of acantharians are composed of crystalline strontium sulphate, known as celestite, precipitated from seawater in the upper ocean."