Conchoidal, Uneven, ConchoidalArthur Thomas, Gemstones (2009)
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
(Mg,Fe2+ )Al 2O 4Gemdat.org , Management Team (2012) More from other references
CaCO 3Ulrich Henn and Claudio C.