Mineral Species: Orthoclase

Chemical Formula: KAlSi3O8

Chemical Name: Potassium Aluminium Silicate

Mineral Class: Tectosilicate

Mineral Notes: Orthoclase is a polymorph of other rock-forming silicate minerals that share the same chemistry, but have different crystal structures. If positive identification between these minerals can not be made by field methods, then the specimen may simply be referred to as a potassium feldspar or K-spar.