Uneven, Uneven, Gemstones of the world (2001) More from other references
ConchoidalAnthony et al, Handbook of mineralogy (2001), ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle, Conchoidal
H 4Mg 3Si 2O 9Walter Schumann , Gemstones of the world (2001) More from other references
CaBe 2(PO 4) 2Michael OâDonoghue , Gems, Sixth Edition (2006)