Gemstones of the world (2001), Difficult, Splintery
Conchoidal, ConchoidalAnthony et al, Conchoidal, Brittle, Conchoidal
Nephrite: Ca2(Mg,Fe)5Si8O22(OH)2 Jadeite: NaAlSi2O6
(Zn,Cu)Al 6(PO 4) 4(OH) 8 · 4H 2OMichael OâDonoghue , Gems, Sixth Edition (2006)