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