Sub-Conchoidal, ConchoidalArthur Thomas, Conchoidal, Uneven
Conchoidal, Uneven, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
(Fe,Mn)AlPO 4(OH) 2 -H 2OArthur Thomas , Gemstones (2009)
Ca 3Al 2(SiO 4) 3Arthur Thomas , Gemstones (2009)