ConchoidalGemdat.org, Management Team (2012), ConchoidalGemdat.org, Management Team (2012)
Splintery, Granular, Splintery, Granular, Gemstones (2009)
(Fe,Mg) 3Al 2(SiO 4) 3gemdat.org , Management Team (2012)
Ca 2(Mg,Fe) 5(OH) 2Walter Schumann , Gemstones of the world (2001) More from other references