Uneven, Uneven, ConchoidalWalter Schumann, Gemstones of the world (2001)
UnevenAnthony et al, Handbook of mineralogy (2001), UnevenAnthony et al, Handbook of mineralogy (2001)
Mg 2Al 4Si 5O 18Ulrich Henn and Claudio C.
Na(Mn2+ ,Ca) 2Si 3O 8(OH)Michael OâDonoghue , Gems, Sixth Edition (2006)