ConchoidalGemdat.org, Management Team (2012), ConchoidalGemdat.org, Management Team (2012)
Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle, Conchoidal, Brittle
(Fe,Mg) 3Al 2(SiO 4) 3gemdat.org , Management Team (2012)
(Na,Ca,K) 8(Si,Al) 12O 24(SO 4,Cl,CO 3) 3(H 2O)Arthur Thomas , Gemstones (2009)