What is perthite?

Perthite is a type of feldspar mineral that is a combination of sodium and potassium feldspar. It is named after the city of Perth in Scotland, where it was first described. Perthite is characterized by its distinctive exsolution texture, in which alternating layers of sodium-rich and potassium-rich feldspar separate out due to temperature changes during the cooling of the mineral.

Perthite can be found in a variety of igneous rocks, including granite, granodiorite, and pegmatite. It is typically white, gray, or pink in color and has a pearly luster.

Perthite is commonly used in the manufacture of ceramics, glass, and as a gemstone in jewelry. It is also used in the production of porcelain and as a flux in metallurgy.

Overall, perthite is a unique and valuable mineral that is prized for its beauty and versatility in various industries.