Subconchoidal, ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle, Conchoidal
Gemstones of the world (2001), Difficult, Splintery
Ca 6Si 2(CO 3) 2(SO 4) 2(OH) 12 · 24H 2OUlrich Henn and Claudio C.
Nephrite: Ca2(Mg,Fe)5Si8O22(OH)2 Jadeite: NaAlSi2O6