Uneven, Uneven, Gemstones of the world (2001) More from other references
Sub-Conchoidal, ConchoidalArthur Thomas, Conchoidal, Uneven
H 4Mg 3Si 2O 9Walter Schumann , Gemstones of the world (2001) More from other references
(Fe,Mn)AlPO 4(OH) 2 -H 2OArthur Thomas , Gemstones (2009)