A borosilicate of lime commonly occuring in glassy,, greenish crystals.

a silicate containing boron and calcium, found as glassy crystals in various colors. CaBSiO4(OH) [from Greek dateisthai to divide + English -ite] [AHDOS

Datolite is a calcium boron hydroxide nesosilicate, CaBSiO4(OH). Datolite crystallizes in the monoclinic system forming prismatic crystals and nodular masses. The luster is vitreous and may be brown, yellow, light green or colorless.