ConchoidalWalter Schumann, Gemstones of the world (2001), ConchoidalWalter Schumann, Gemstones of the world (2001), Brittle, Metallic
ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle