mineral

Potassium Feldspar

Orthoclase (KAlSi3O8)

Hardness: 6 on Mohs scale; Color: Pink, salmon-orange, or flesh-red; Luster: Vitreous to pearly; Crystal Structure: Monoclinic; Cleavage: Two planes at 90 degrees; Specific Gravity: 2.55-2.63.

Hardness: 6 on Mohs scale
Color: Pink, salmon-orange, or flesh-red
Luster: Vitreous to pearly

Identified May 31, 2026More mineral →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 6 on Mohs scale; Color: Pink, salmon-orange, or flesh-red; Luster: Vitreous to pearly; Crystal Structure: Monoclinic; Cleavage: Two planes at 90 degrees; Specific Gravity: 2.55-2.63.

Formation & geological history

Forms in igneous rocks like granite and syenite through the crystallization of magma, as well as in high-grade metamorphic rocks and as a constituent in some sedimentary sandstones.

Uses & applications

Widely used in the manufacture of glass and ceramics (pottery, porcelain, and enamel). Occasionally used as a semi-precious gemstone (Moonstone variant) or for mineral collecting.

Geological facts

Potassium feldspar is one of the most abundant minerals in the Earth's continental crust and is the primary reason why many granites have a pinkish or reddish hue.

Field identification & locations

Identify in the field by its distinct pink/salmon color and two cleavages meeting at right angles. It can be distinguished from quartz by its cleavage and lack of conchoidal fracture. Common in mountainous regions with granitic bedrock.