Hackly Jagged, torn surfaces, (e.g. fractured metals)., torn surfaces, (e.g. fractured metals).
UnevenArthur Thomas, Gemstones (2009), UnevenArthur Thomas, Gemstones (2009)
Cu
Ca 2(Mg,Al) 6(Si,Al,B) 6O 20Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references