Uneven, Uneven, Management Team (2012), Conchoidal, Brittle
Conchoidal, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Conchoidal, Brittle
Fe 3O 4Ulrich Henn and Claudio C.
CuSiO 2(OH) 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references