Rock Identifier
Feldspar (Orthoclase) (Potassium Feldspar (KAlSi3O8)) — mineral
mineral

Feldspar (Orthoclase)

Potassium Feldspar (KAlSi3O8)

AI-generated identification · may be incorrect

Hardness: 6 on Mohs scale; Color: Pink, salmon, or orange-beige; Luster: Vitreous to pearly; Crystal Structure: Monoclinic; Cleavage: Two directions at 90 degrees; Specific Gravity: 2.55–2.63

Hardness
6 on Mohs scale
Color
Pink, salmon, or orange-beige
Luster
Vitreous to pearly
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Physical properties

Hardness: 6 on Mohs scale; Color: Pink, salmon, or orange-beige; Luster: Vitreous to pearly; Crystal Structure: Monoclinic; Cleavage: Two directions at 90 degrees; Specific Gravity: 2.55–2.63

Formation & geological history

Formed primarily in igneous rocks like granite and pegmatites, as well as some metamorphic rocks, through the cooling of magma or hydrothermal activity. It is one of the most abundant minerals in the Earth's crust.

Uses & applications

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

Geological facts

Feldspar makes up about 41% of the Earth's continental crust by weight. The name is derived from the German 'Feldspat', meaning 'field spar'.

Field identification & locations

Identify by its blocky shape and pinkish color. It is harder than glass but can be scratched by quartz. Common in granitic terrains worldwide.

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