Rock Identifier
Raw Sunstone (Plagioclase Feldspar (Na, Ca)(Al, Si)4O8) — mineral
mineral

Raw Sunstone

Plagioclase Feldspar (Na, Ca)(Al, Si)4O8

Hardness: 6-6.5 on Mohs scale; Color: Reddish-orange, pink, or brownish with white/clear areas; Luster: Vitreous to pearly; Crystal structure: Triclinic; Cleavage: Perfect in two directions; Specific gravity: 2.62-2.67

Hardness
6-6
Color
Reddish-orange, pink, or brownish with white/clear areas
Luster
Vitreous to pearly
Identified More mineral
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Physical properties

Hardness: 6-6.5 on Mohs scale; Color: Reddish-orange, pink, or brownish with white/clear areas; Luster: Vitreous to pearly; Crystal structure: Triclinic; Cleavage: Perfect in two directions; Specific gravity: 2.62-2.67

Formation & geological history

Forms in igneous rocks like basalt and andesite, often as phenocrysts. The red/orange coloring is caused by tiny inclusions of hematite or copper (schiller effect) and typically forms in volcanic lava flows.

Uses & applications

Used primarily as a gemstone for jewelry (cabochons, beads, faceted stones) and as a collector's specimen. Known for its 'aventurescence' or metallic glitter.

Geological facts

Sunstone is the official state gemstone of Oregon in the USA. While most sunstone contains hematite, the rare Oregon variety contains inclusions of pure copper.

Field identification & locations

Identify by its characteristic metallic glitter (schiller) when rotated under light and its pinkish-orange hue contrasted against lighter feldspar. Commonly found in Oregon (USA), Norway, Tanzania, and India.