Uneven, Sub-Conchoidal, UnevenWalter Schumann, Gemstones of the world (2001) More from other references, Brittle, Metallic
Uneven
ZnCO 3Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
K(Al,Cr) 3Si 3O 10(OH) 2Gemdat.org , Management Team (2012)