Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001), Conchoidal, Brittle
Gemstones of the world (2001), Difficult, Splintery
Mg 3(SiO 4)(F,OH) 2Anthony et al , Handbook of Mineralogy (2001)
Nephrite: Ca2(Mg,Fe)5Si8O22(OH)2 Jadeite: NaAlSi2O6