Uneven, Uneven, ConchoidalGemdat.org, Management Team (2012)
Subconchoidal, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
Mg 3Al 2(SiO 4) 3 -Mn2+3Al 2(SiO 4) 3Gemdat.org , Management Team (2012)
CaCO 3Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references