Gemstones of the world (2001), Difficult, Splintery
Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle, Conchoidal
Nephrite: Ca2(Mg,Fe)5Si8O22(OH)2 Jadeite: NaAlSi2O6
(Ca,Na)(Mg,Fe,Al)Si 2O 6Anthony et al , Handbook of Mineralogy (2001)