ConchoidalWalter Schumann, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Brittle, Metallic
UnevenAnthony et al, Handbook of mineralogy (2001), UnevenAnthony et al, Handbook of mineralogy (2001), Brittle, Conchoidal
Be 2BO 3(OH)Ulrich Henn and Claudio C.
CaMoO 4Michael OâDonoghue , Gems, Sixth Edition (2006)