Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001)
UnevenArthur Thomas, Gemstones (2009), UnevenArthur Thomas, Gemstones (2009), Uneven
NaFe3+3Fe3+6(BO 3) 3Si 6O 18(O,OH) 4Anthony et al , Handbook of Mineralogy (2001)
Mg 6Cr 2(CO 3)(OH) 16 · 4H 2OMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references