mineral

Sunstone

Oligoclase or Andesine (Plagioclase Feldspar) - (Ca, Na)((Al, Si)2Si2O8)

AI-generated identification · may be incorrect

Hardness: 6-6.5 (Mohs scale); Color: Yellow, orange, or reddish with metallic 'shiller' or aventurescence; Luster: Vitreous; Crystal Structure: Triclinic; Cleavage: Perfect in two directions at 90 degrees; Specific Gravity: 2.62–2.65

Hardness: 6-6
Luster: Vitreous

Identified March 25, 2026More mineral →

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Physical properties

Formation & geological history

Formed in igneous rocks like basalt flows or granitic pegmatites. The specific orange-gold appearance is caused by tiny inclusions of copper (in Oregon Sunstone) or hematite/goethite platelets that reflect light.

Uses & applications

Primarily used as a gemstone in jewelry (rings, pendants, earrings), and as a collector's mineral specimen. Some low-grade material is used for decorative carvings.

Geological facts

Oregon sunstone is unique globally because its color and 'shiller' effect are caused by elemental copper rather than iron minerals. It was named the official state gemstone of Oregon in 1987.

Field identification & locations

Identify by looking for the 'aventurescence' (a metallic glitter) when tilted under light. Commonly found in the high desert of South-Central Oregon, USA, and parts of Norway and Tanzania. In the field, look for translucent honey-colored crystals in weathered volcanic rock.