Gemstones of the world (2001), Difficult, Splintery
Uneven, ConchoidalArthur Thomas, Gemstones (2009), Brittle, Metallic
Nephrite: Ca2(Mg,Fe)5Si8O22(OH)2 Jadeite: NaAlSi2O6
Mg 2Si 2O 6Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references