pollucite

/ (ˈpɒljʊˌsaɪt, pəˈluːˌsaɪt) /

noun

a colourless rare mineral consisting of a hydrated caesium aluminium silicate, often containing some rubidium. It occurs in coarse granite, esp in Manitoba, and is an important source of caesium. Formula: CsAlSi 2 O 6 . 1/2 H 2 O

Word Origin for pollucite

C19: from Latin polluc-, stem of Pollux + -ite 1; originally called pollux, alluding to Castor and Pollux, since it was associated with another mineral called castor or castorite