mineral
Potassium Feldspar (Orthoclase / Microcline)
KAlSi3O8 (Potassium Aluminum Silicate)
AI-generated identification · may be incorrectHardness: 6 on Mohs scale. Color: Pinkish-orange, salmon, to brownish-pink. Luster: Vitreous to pearly on cleavage surfaces. Cleavage: Two directions meeting at nearly 90 degrees. Specific gravity: 2.56-2.59.
- Hardness
- 6 on Mohs scale
- Color
- Pinkish-orange, salmon, to brownish-pink
- Luster
- Vitreous to pearly on cleavage surfaces
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Physical properties
Hardness: 6 on Mohs scale. Color: Pinkish-orange, salmon, to brownish-pink. Luster: Vitreous to pearly on cleavage surfaces. Cleavage: Two directions meeting at nearly 90 degrees. Specific gravity: 2.56-2.59.
Formation & geological history
Formed as a major constituent of intrusive igneous rocks such as granites and pegmatites through slow cooling of silicate magma, as well as in high-grade metamorphic rocks.
Uses & applications
Widely used in the manufacture of ceramics, glass, enamel, and abrasives. High-grade aesthetic specimens or moonstone varieties are used as gemstones and in mineral collections.
Geological facts
Feldspars make up over 50% of Earth's crust. Potassium feldspar is defined as the defining mineral for hardness 6 on Friedrich Mohs' scale of mineral hardness.
Field identification & locations
Identified in the field by its distinctive pink/salmon color, blocky cleavage fragments, hardness that scratches glass but is scratched by quartz, and pearly luster on flat cleavage planes. Very common worldwide in granite regions.
