Uneven, ConchoidalArthur Thomas, Gemstones (2009), Brittle, Metallic
Conchoidal, Conchoidal, Gemstones of the world (2001) More from other references
Mg 2Si 2O 6Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
SiO 2 · nH 2OGemdat.org , Management Team (2012)