Conchoidal, Conchoidal, Gemstones of the world (2001)
ConchoidalGemdat.org, Management Team (2012), ConchoidalGemdat.org, Management Team (2012)
SiO 2 · nH 2OWalter Schumann , Gemstones of the world (2001) More from other references
(Fe,Mg) 3Al 2(SiO 4) 3gemdat.org , Management Team (2012)