mineral

Feldspar (Potassium Feldspar / Orthoclase)

KAlSi3O8 (Potassium Aluminum Silicate)

AI-generated identification · may be incorrect

Mohs hardness of 6, salmon-pink to reddish-orange color, vitreous to pearly luster, monoclinic or triclinic crystal structure, perfect cleavage in two directions at near 90 degrees, specific gravity 2.56-2.58.

Identified July 26, 2026More mineral →

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Physical properties

Formation & geological history

Forms primarily in felsic igneous rocks such as granite and pegmatites through cooling magma, as well as in high-grade metamorphic rocks and detrital sedimentary rocks.

Uses & applications

Widely used in the manufacture of glass, ceramics, pottery glazes, porcelain, and mild abrasives. High-grade gem varieties (like moonstone or sunstone) are used in jewelry.

Geological facts

Feldspars are the most abundant group of minerals in the Earth's continental crust, making up about 60% of terrestrial rocks.

Field identification & locations

Identified by its distinctive salmon-pink color, blocky cleavage faces that reflect light, and hardness of 6 (scratches glass). Common worldwide in granitic terrains including Brazil, India, Madagascar, and North America.