mineral

Potassium Feldspar

K-Feldspar (Orthoclase/Microcline) KAlSi3O8

AI-generated identification · may be incorrect

Hardness: 6 (Mohs); Color: Salmon pink to reddish-orange; Luster: Vitreous to pearly; Crystal structure: Monoclinic or Triclinic; Cleavage: Two directions at 90 degrees; Specific Gravity: 2.5-2.6

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

Identified July 4, 2026More mineral →

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Physical properties

Hardness: 6 (Mohs); Color: Salmon pink to reddish-orange; Luster: Vitreous to pearly; Crystal structure: Monoclinic or Triclinic; Cleavage: Two directions at 90 degrees; Specific Gravity: 2.5-2.6

Formation & geological history

Forms primarily in igneous rocks like granite and syenite through the cooling of silica-rich magma; also found in metamorphic rocks like gneiss and as clasts in sedimentary rocks.

Uses & applications

Used in the manufacture of glass and ceramics, as a filler in paints and plastics, and occasionally as a gemstone (moonstone or sunstone varieties).

Geological facts

Feldspars are the most abundant mineral group in Earth's crust, making up about 60% of terrestrial rocks. The pink color in this specimen is often due to trace amounts of iron or hematite inclusions.

Field identification & locations

Identify by its distinctive salmon-pink color, blocky cleavage planes that reflect light, and its ability to scratch glass but be scratched by quartz. Common in granitic terrains worldwide.