mineral

Potassium Feldspar (Orthoclase / Microcline)

KAlSi3O8

AI-generated identification · may be incorrect

Hardness: 6 on Mohs scale. Color: Salmon-pink to reddish-brown. Luster: Vitreous to pearly. Crystal system: Monoclinic or Triclinic. Cleavage: Two directions at nearly 90 degrees.

Hardness: 6 on Mohs scale
Color: Salmon-pink to reddish-brown
Luster: Vitreous to pearly

Identified July 26, 2026More mineral →

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Physical properties

Hardness: 6 on Mohs scale. Color: Salmon-pink to reddish-brown. Luster: Vitreous to pearly. Crystal system: Monoclinic or Triclinic. Cleavage: Two directions at nearly 90 degrees.

Formation & geological history

Forms in igneous rocks like granite and pegmatites through crystallization of magma, as well as in high-grade metamorphic rocks.

Uses & applications

Used extensively in the glassmaking and ceramics industries, as well as a constituent of dimension stone (granite counter tops and building facades). Specimen collecting.

Geological facts

Although placed in the box labeled 'Feldspar' (above) or near 'Jasper' in this collection grid, this salmon-pink specimen exhibits classic feldspar cleavage surfaces, pearly-to-vitreous luster, and blocky habit typical of K-feldspar rather than dense microcrystalline quartz jasper.

Field identification & locations

Identified by its distinctive salmon-pink color, blocky cleavage planes meeting at right angles, and hardness of 6. Found abundantly worldwide in continental crustal rocks.