English

Noun

1. A mineral of silica-poor igneous, plutonic and volcanic rocks. Chemically, Leucite is a potassium feldspar with insufficient silica to satisfy the chemical bonds. Because of the unfilled bonds, Leucite weathers rapidly and can only be seen as inclusions in freshly broken rock.

• Chemical composition: Potassium aluminum subsilicate, KAlSi₂O₆

• Physical properties:
  • Moh's Hardness: 5.5-6.0
  • Specific gravity: 2.4-2.5
  • Color: Gray to white to colorless
  • Luster: Glassy, but rapidly weathers to a dull surface
  • Fracture: Conchoidal
  • Cleavage: Imperfect dodecahedral
  • Habit: Tetragonal-trapezohedral (pseudo-isometric)