Uneven, Uneven, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Brittle, Conchoidal
Not Available
PbCO 3Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
(Mg,Fe)Al 2O 4Gemdat.org , Management Team (2012)