Uneven, Uneven, Gemstones of the world (2001) More from other references
Brittle, Metallic, Brittle, Metallic
H 4Mg 3Si 2O 9Walter Schumann , Gemstones of the world (2001) More from other references
CaZnSiO 4 · H 2OAnthony et al , Handbook of mineralogy (2001)