Uneven, Uneven, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Conchoidal, Brittle
Not Available
CaB 2(SiO 4) 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Ca(Nd,Ce,La) 2(CO 3) 3F 2Ulrich Henn and Claudio C.