Uneven, Yellow, White, UnevenWalter Schumann, Gemstones of the world (2001) More from other references, Brittle, Metallic
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009), Brittle, Uneven
Ca2Al2Si3O12(OH)
Mg 3Al 6(Si,Al,B) 5O 21(OH)Walter Schumann , Gemstones of the world (2001) More from other references