Noun

1. A variety of orthoclase feldspar found as tabular crystals embedded in volcanic rocks. It sometimes reflects a blue sheen along crystal planes. This phenomenon is called adularescence, and sanidine with this property is called moonstone.

• Chemical composition: Potassium aluminum silicate, $KAlSi\_3O\_8$

• Physical properties:
  • Moh's Hardness: 6.0
  • Specific gravity: 2.6
  • Color: white, flesh, yellow, pink
  • Luster: glassy
  • Fracture: conchoidal
  • Habit: tabular. Well developed crystal faces are often highly reflective.