ConchoidalWalter Schumann, Gemstones of the world (2001), ConchoidalWalter Schumann, Gemstones of the world (2001)
Uneven, Uneven, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Conchoidal, Brittle
SiO 2(+Al 2O 3)Walter Schumann , Gemstones of the world (2001)
Zn 4Si 2O 7(OH) 2H 2OMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references