Uneven, Uneven, Gems, Sixth Edition (2006)
Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001), Conchoidal, Brittle
CaAl 2Si 2O 8Michael OâDonoghue , Gems, Sixth Edition (2006)
Na 8Al 6Si 6O 24(SO 4) · H 2OAnthony et al , Handbook of Mineralogy (2001)