Uneven, UnevenArthur Thomas, Gemstones (2009)
Uneven, Uneven, Irregular, Management Team (2012), Conchoidal, Brittle
Cu 5(SiO 3) 4(OH) 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Ca 3Al 2(SiO 4) 3-x(OH) 4x (x=0.2 to 1.5)Anthony et al , Handbook of mineralogy (2001)