Uneven, Uneven, Gems, Sixth Edition (2006), Uneven, Conchoidal
Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001)
NaAlSi 3O 8Michael OâDonoghue , Gems, Sixth Edition (2006)
Ca 5(PO 4) 3FAnthony et al , Handbook of mineralogy (2001)