Uneven, Uneven, ConchoidalWalter Schumann, Gemstones of the world (2001)
ConchoidalWalter Schumann, Gemstones of the world (2001), ConchoidalWalter Schumann, Gemstones of the world (2001), Brittle, Metallic
2,1 basal ; 2,1 prismatic ; 3,1 pinacoidal
{010} Perfect
Plagioclase Feldspar s: (Na,Ca)Al1-2Si3-2O8 Orthoclase Feldspar : KAlSi3O8
BeAlSiO 4(OH)Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references