%euclase%

pos>n. [ Gr. e'y^ well, easily + &unr_; to break. Cf. F. euclase, G. euklas. See named from its brittleness. ] (Min.) A brittle gem occurring in light green, transparent crystals, affording a brilliant clinodiagonal cleavage. It is a silicate of alumina and glucina. [ 1913 Webster ]