Uneven, Uneven, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Conchoidal, Brittle
ConchoidalAnthony et al, Handbook of mineralogy (2001), ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle, Conchoidal
Fe 2O 3Arthur Thomas , Gemstones (2009)
CaBe 2(PO 4) 2Michael OâDonoghue , Gems, Sixth Edition (2006)