Gemstones of the world (2001), Difficult, Splintery
UnevenAnthony et al, Handbook of mineralogy (2001), UnevenAnthony et al, Handbook of mineralogy (2001), Uneven
Nephrite: Ca2(Mg,Fe)5Si8O22(OH)2 Jadeite: NaAlSi2O6
Fe3+ PO 4 · 2H 2OAnthony et al , Handbook of Mineralogy (2001)