ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009), (e.g. graphite).
Uneven, Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Even
{110} Distinct, {001} Indistinct, {100} Indistinct
Perfect {010} imperfect {100}