the GNU version of the Collaborative International Dictionary of English
noun.
A colorless transparent mineral, resembling quartz, occurring with castor or castorite on the island of Elba. It is a silicate of alumina and cæsia. Called also pollux.
noun.
A colorless transparentmineral of the zeolite family consisting of hydrous cesium aluminum silicate and occurring massive or crystallizing in cubes.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
noun.
a rare mineral that is an important source of cesium
Word Usage
"Most cesium is retrieved from the mineral pollucite."