Uneven, Uneven, ConchoidalWalter Schumann, Gemstones of the world (2001)
Uneven, Uneven, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Brittle, Conchoidal
2,1 basal ; 2,1 prismatic ; 3,1 pinacoidal
Good [110] and [021]
Plagioclase Feldspar s: (Na,Ca)Al1-2Si3-2O8 Orthoclase Feldspar : KAlSi3O8
PbCO 3Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references