mineral
Potassium Feldspar
K-Feldspar (Orthoclase/Microcline), KAlSi3O8
Hardness: 6 (Mohs); Color: Pink, salmon, or tan; Luster: Vitreous to pearly; Crystal structure: Monoclinic or Triclinic; Cleavage: Two directions at 90 degrees; Specific gravity: 2.55-2.63
- Hardness
- 6 (Mohs)
- Color
- Pink, salmon, or tan
- Luster
- Vitreous to pearly
Identified More mineral →
Explore Potassium Feldspar in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6 (Mohs); Color: Pink, salmon, or tan; Luster: Vitreous to pearly; Crystal structure: Monoclinic or Triclinic; Cleavage: Two directions at 90 degrees; Specific gravity: 2.55-2.63
Formation & geological history
Forms primarily in igneous rocks like granite and pegmatite through the cooling of magma, as well as in metamorphic rocks and some sandstones.
Uses & applications
Used in the manufacturing of glass and ceramics (porcelain), as a mild abrasive in scouring powders, and occasionally as a gemstone (moonstone/amazonite).
Geological facts
Feldspar is the most abundant mineral group in the Earth's crust, making up about 41% of its mass by weight. The pink color is often caused by micro-inclusions of hematite or defects in the crystal lattice.
Field identification & locations
Identify in the field by its distinct pink/flesh color, two cleavage planes meeting at nearly right angles, and its inability to be scratched by a steel knife (hardness). It is found worldwide in continental crust exposures.
More like this
Other mineral specimens
Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
sedimentary
Sandstone with Mineral Veining or Crust
Sedimentary Sandstone (mostly SiO2 with Fe2O3 tinting)
sedimentary
Schist
Schist
Metamorphic
Potassium Feldspar (Orthoclase)
Orthoclase (KAlSi3O8)
mineral
Gypsum (variety Selenite or Alabaster)
Calcium sulfate dihydrate (CaSO4·2H2O)
Mineral
Nephrite Jade
Nephrite
Mineral/Rock