Sub-Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Brittle
UnevenAnthony et al, Handbook of mineralogy (2001), UnevenAnthony et al, Handbook of mineralogy (2001)
Cu2H2Si2O5(OH)4
Na(Mn2+ ,Ca) 2Si 3O 8(OH)Michael OâDonoghue , Gems, Sixth Edition (2006)