Bytownite is a calcium rich member of the plagioclase solid solution series of feldspar minerals with composition between anorthite and labradorite.It is usually defined as having between 70 and 90 %An (formula: (Ca 0.7-0.9,Na 0.3-0.1)[Al(Al,Si)Si 2 O 8]).Like others of the series, bytownite forms grey to white triclinic crystals commonly ...
