Gemstones (2009), Flexible Flexible fragments.
Conchoidal, Brittle, Metallic, Conchoidal, Handbook of mineralogy (2001)
Al 2Si 4O 10(OH) 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
(Mg,Fe2+ ) 3Si 2O 5(OH) 4Anthony et al , Handbook of mineralogy (2001)