Uneven, Uneven, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
ConchoidalGemdat.org, Management Team (2012), ConchoidalGemdat.org, Management Team (2012)
(Mg,Fe) 5(SiO 4) 2(F,OH) 2Ulrich Henn and Claudio C.
(Fe,Mg) 3Al 2(SiO 4) 3gemdat.org , Management Team (2012)