Micaceous, Brittle
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
KAl 2AlSi 3O 10(OH) 2Walter Schumann , Gemstones of the world (2001) More from other references
(Ca,Mg,Mn)SiO 3Gemdat.org , Management Team (2012)