mineral

Potassium Feldspar (Orthoclase)

KAlSi3O8 (Potassium Aluminum Silicate)

Hardness: 6.0 on Mohs scale; Color: Pinkish-red to salmon; Luster: Vitreous to pearly; Crystal structure: Monoclinic; Cleavage: Two directions at 90 degrees; Specific Gravity: 2.55-2.63.

Hardness: 6
Color: Pinkish-red to salmon
Luster: Vitreous to pearly

Identified June 19, 2026More mineral →

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Physical properties

Hardness: 6.0 on Mohs scale; Color: Pinkish-red to salmon; Luster: Vitreous to pearly; Crystal structure: Monoclinic; Cleavage: Two directions at 90 degrees; Specific Gravity: 2.55-2.63.

Formation & geological history

Formed through the cooling of silica-rich magma in plutonic igneous rocks like granite, or within metamorphic rocks like gneiss. This specimen appears water-worn, likely from a fluvial or glacial deposit.

Uses & applications

Used in the manufacture of glass and ceramics (porcelain), as a filler in paints and plastics, and as an abrasive in scouring powders. Some varieties are used as gemstones (Moonstone).

Geological facts

Potassium feldspar is one of the most abundant minerals in the Earth's continental crust. Its pink color is often due to microscopic inclusions of iron oxides or impurities within the crystal lattice.

Field identification & locations

Identify by its distinct salmon-pink color, its hardness (will scratch glass but not quartz), and its characteristic planar cleavage surfaces. It is a major component of pink granite.

Other mineral specimens

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

mineral