Uneven, Uneven, Gemstones of the world (2001) More from other references
Handbook of mineralogy (2001), Difficult, Fibrous
H 4Mg 3Si 2O 9Walter Schumann , Gemstones of the world (2001) More from other references
Ca 6Si 6O 17(OH) 2Michael OâDonoghue , Gems, Sixth Edition (2006)