English

Etymology

Noun

1. A plagioclase feldspar, the fifth member of the Albite-Anorthite solid solution series. Bytownite is rare, and normally occurs in small grains in lime-rich igneous rocks. Clear pale yellow crystals have come from Mexico and Oregon.

• Chemical composition: Calcium sodium aluminum silicate, $Ca\_xNa\_xAlSi\_3O\_8$

• Physical properties:
  • Moh's Hardness: 6.0
  • Specific gravity: 2.74
  • Color: White, pale yellow, shades of gray
  • Luster: glassy
  • Fracture: conchoidal
  • Cleavage: two good at about 94º to each other
  • Habit: Triclinic - pinacoidal. Crystals are rare.