mineral

Orthoclase Feldspar (Sunstone variety)

KAlSi3O8 (Potassium Aluminum Silicate)

Hardness: 6 on Mohs scale; Color: Peach, salmon pink, or orange; Luster: Vitreous to pearly; Crystal structure: Monoclinic; Cleavage: Perfect in two directions at 90 degrees; Specific Gravity: 2.55–2.63

Hardness: 6 on Mohs scale
Color: Peach, salmon pink, or orange
Luster: Vitreous to pearly

Identified April 11, 2026More mineral →

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Physical properties

Formation & geological history

Formed in felsic igneous rocks (granite and pegmatite) and metamorphic rocks. It crystallizes from cooling magma or during the recrystallization of minerals under intense heat and pressure.

Uses & applications

Used in the manufacture of glass and ceramics (as a flux) and as an abrasive. Attractive colored specimens like this are used in lapidary work, jewelry, and for geological collections.

Geological facts

Feldspar is the most abundant mineral group in the Earth's crust, making up about 60% of terrestrial rocks. The pink color is often caused by micro-inclusions of hematite or trace structural impurities.

Field identification & locations

Identify by its 90-degree cleavage planes, peach-pink color, and ability to scratch glass but not quartz. Commonly found in mountainous regions with exposed granite like the Appalachians, Rockies, or the Scandinavian shield.

Other mineral specimens

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

mineral

Epidote

Epidote - Ca2(Al2,Fe3+)3(SiO4)3(OH)

mineral