mineral

Potassium Feldspar

Orthoclase (KAlSi3O8)

Hardness: 6 (Mohs scale); Color: pink to reddish-orange; Luster: Vitreous to pearly; Crystal structure: Monoclinic; Cleavage: Two directions at 90 degrees; Specific gravity: 2.55-2.63.

Hardness: 6 (Mohs scale)
Color: pink to reddish-orange
Luster: Vitreous to pearly

Identified May 9, 2026More mineral →

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Physical properties

Hardness: 6 (Mohs scale); Color: pink to reddish-orange; Luster: Vitreous to pearly; Crystal structure: Monoclinic; Cleavage: Two directions at 90 degrees; Specific gravity: 2.55-2.63.

Formation & geological history

Forms in igneous rocks like granite and syenite through the cooling of magma, and also appears in metamorphic rocks. Commonly associated with pegmatites.

Uses & applications

Used in the manufacture of glass, ceramics, and enamels. High-quality varieties like moonstone are used in jewelry.

Geological facts

Feldspar is the most abundant group of minerals in the Earth's crust, making up about 60% of terrestrial rocks. The pink color in this specimen is due to tiny inclusions of hematite or structural defects in the crystal lattice.

Field identification & locations

Look for the distinct pink to fleshy salmon color and the flat, reflective cleavage planes when broken. Commonly found in granitic terrains and river gravels derived from mountains.