Glossary of Terms
Potassium feldspar group
Group name for three very closely related minerals: Orthoclase, Sanidine, and Microcline. These three feldspar minerals have equal physical properties. They are all composed of the same elements, but their crystal structure differs. It is sometimes impossible to tell apart one of these minerals from another without x-ray analysis. Due to the difficulty of determining the exact classification, all these three minerals may be called "Potassium Feldspar" without further classification. Sanidine and Microcline are wrongly classified as a variety of Orthoclase in many reference guides, when, in fact, they are separate minerals.
The mineral Anorthoclase is usually also classified with the potassium feldspars.
Synonyms for potassium feldspar include:
- Alkali Feldspar