'Pollucite' definitions:

Definition of 'pollucite'

(from WordNet)
noun
A rare mineral that is an important source of cesium

Definition of 'Pollucite'

From: GCIDE
  • Pollucite \Pol"lu*cite\, n. [See Pollux, and 4th Castor.] (Min.) A colorless transparent mineral, resembling quartz, occurring with castor or castorite on the island of Elba. It is a silicate of alumina and c[ae]sia. Called also pollux. [1913 Webster]