Datolite

General Information: Chemical Formula:CaBSiO4(OH) Composition:(Molecular Weight = 159.98 gm)Calcium 25.05 % CaSilicon 17.56 % SiBoron 6.76 % B Hydrogen 0.63 % H Oxygen 50.00 % O  Empirical Formula: CaB(SiO4)(OH) Environment:Secondary mineral in basic igneous rocks. Locality:Diabases of the Connecticut River valley, USA. Name Origin:From the Greek, dateisthai, meaning "to divide," because granular aggregates crumble readily.Physical Properties: Cleavage:None Color:brown, colorless, yellow, white, or light green. Density:2.8 - 3, Average = 2.9 Diaphaniety:Transparent to translucent Habits:Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline)., Granular - Generally occurs as anhedral to subhedral crystals in matrix., Porcelainous - Fine-grained, translucent massive material like broken china Hardness:5.5 - Knife Blade Luminescence:None. Luster:Vitreous (Glassy) Streak:whiteMore details...