Uneven, Subconchoidal, ConchoidalArthur Thomas, Gemstones (2009), Uneven, Subconchoidal, Brittle, Metallic, Brittle, Metallic
Gemstones of the world (2001), Difficult, Splintery
Zn 2(AsO 4)(OH)Michael OâDonoghue , Gems, Sixth edition (2006)
Nephrite: Ca2(Mg,Fe)5Si8O22(OH)2 Jadeite: NaAlSi2O6