Pronunciation: ' yü- ˌ kl ā s, - ˌ kl ā z
Function: noun
Etymology: French, from eu- (fr. L) + Greek klasis breaking, from klan to break
Date: 1804
: a mineral that consists of a brittle silicate of beryllium and aluminum in pale yellow, green, or blue prismatic crystals and is used especially as a gemstone