Conchoidal, Brittle, Conchoidal
Uneven, Sub-Conchoidal, UnevenWalter Schumann, Gemstones of the world (2001) More from other references, Brittle, Metallic
[ ]Na2(Mg3Al2)Si8O22(OH)2
ZnCO 3Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references