mineral

Potassium Feldspar

K-Feldspar (KAlSi3O8)

Hardness: 6 on Mohs scale; Color: Pink, salmon, or peach-colored; Luster: Vitreous to pearly; Crystal Structure: Monoclinic or triclinic; Cleavage: Two directions at nearly 90 degrees; Specific Gravity: 2.55-2.63

Hardness: 6 on Mohs scale
Color: Pink, salmon, or peach-colored
Luster: Vitreous to pearly

Identified June 7, 2026More mineral →

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Physical properties

Formation & geological history

Commonly forms in igneous rocks like granite and pegmatites through the cooling of silica-rich magma; also found in metamorphic rocks like gneiss during regional metamorphism.

Uses & applications

Used in the manufacture of glass and ceramics (as a flux), as a filler in paint and rubber, and occasionally as a semi-precious gemstone (like moonstone or amazonite).

Geological facts

Feldspar is the most abundant mineral group in the Earth's crust, making up about 60% of the terrestrial rocks we see. The pink color is often caused by trace amounts of hematite or impurities within the crystal lattice.

Field identification & locations

Identify in the field by its distinct pinkish/flesh color, pearly luster on cleavage planes, and its ability to scratch glass but be scratched by a steel file. Found globally in granitic terrains.