Pink Feldspar (Orthoclase)

Physical Properties

Hardness: 6.0 on Mohs scale; Color: Salmon pink to reddish-brown; 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 intrusive igneous rocks like granite and syenite through the cooling of silica-rich magma or in metamorphic rocks like gneiss. This mineral is common across many geological eras.

Uses & Applications

Extensively used in the manufacture of glass and ceramics, as a mild abrasive in scouring powders, and occasionally as a gemstone (moonstone variant) or for decorative aggregate.

Geological Facts

Orthoclase is one of the ten defining minerals of the Mohs scale of mineral hardness. It is one of the most abundant minerals in the Earth's continental crust.

Field Identification & Locations

Identify in the field by its distinct salmon-pink color, blocky cleavage planes at right angles, and its ability to scratch glass but be scratched by quartz. Common in mountain ranges and granite outcrops.

Identified on: 5/4/2026

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