Uneven, Uneven, Gemstones of the world (2001) More from other references
Uneven, Uneven, ConchoidalGemdat.org, Management Team (2012)
H 4Mg 3Si 2O 9Walter Schumann , Gemstones of the world (2001) More from other references
Mg 3Al 2(SiO 4) 3 -Mn2+3Al 2(SiO 4) 3Gemdat.org , Management Team (2012)