mineral

K-Feldspar (Potassium Feldspar)

Potassium Feldspar (KAlSi3O8)

AI-generated identification · may be incorrect

Hardness: 6 on the Mohs scale; Color: Pink, reddish-brown, white, or gray; Luster: Vitreous to pearly; Crystal structure: Monoclinic or triclinic; Cleavage: Two directions of good cleavage at approximately 90 degrees; Specific gravity: 2.5-2.6

Hardness: 6 on the Mohs scale
Color: Pink, reddish-brown, white, or gray
Luster: Vitreous to pearly

Identified July 30, 2026More mineral →

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Physical properties

Formation & geological history

Forms commonly in igneous rocks such as granites, pegmatites, and syenites, as well as in metamorphic gneisses, through crystallization from cooling magma or high-temperature hydrothermal processes.

Uses & applications

Used primarily in the manufacturing of ceramics, glass, as a filler in paints and plastics, and occasionally as a minor gemstone or collector mineral specimen.

Geological facts

Feldspars are the most abundant group of minerals in the Earth's crust, making up about 60% of the crust. The distinctive pink or reddish color in potassium feldspar is often due to microscopic hematite inclusions.

Field identification & locations

Easily identified by its distinct pinkish-orange color, blocky crystal form, and two cleavage planes meeting near 90 degrees. Found worldwide in granitic terrains and pegmatite dykes.