Uneven, Uneven, Gemstones of the world (2001) More from other references
Uneven, Uneven, Gems, Sixth Edition (2006), Uneven, Conchoidal
Ca 10Mg 2Al 4(SiO 4) 5(Si 2O 7) 2(OH) 4Ulrich Henn and Claudio C.
NaAlSi 3O 8Michael OâDonoghue , Gems, Sixth Edition (2006)