igneous
Orthoclase Feldspar (Granitic)
KAlSi3O8 (Potassium Feldspar)
Hardness: 6.0; Color: Salmon pink to reddish-brown; Luster: Vitreous to pearly; Crystal structure: Monoclinic; Cleavage: Two planes at 90 degrees; SG: 2.55-2.63
- Hardness
- 6
- Color
- Salmon pink to reddish-brown
- Luster
- Vitreous to pearly
Identified More igneous →
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Physical properties
Hardness: 6.0; Color: Salmon pink to reddish-brown; Luster: Vitreous to pearly; Crystal structure: Monoclinic; Cleavage: Two planes at 90 degrees; SG: 2.55-2.63
Formation & geological history
Forms in igneous environments such as granites, pegmatites, and syenites through the cooling of silica-rich magma; commonly found in Precambrian cratons.
Uses & applications
Used in the manufacture of glass and ceramics (as a flux) and sometimes as an abrasive or in crushed stone construction.
Geological facts
Orthoclase is one of the most abundant minerals in the Earth's crust and defines the level 6 on the Mohs scale of mineral hardness.
Field identification & locations
Identify by its characteristic pinkish-orange color, blocky cleavage, and inability to be scratched by a steel blade. Commonly found in riverbeds or gravel deposits eroded from granitic mountains.
