Uneven, Uneven, Conchoidal, Uneven, Gems, Sixth Edition (2006)
Subconchoidal, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Brittle, Conchoidal
Perfect on {001}, good on {010}
Perfect on {001}, poor on {201} with 38.5° angle between the two