Mineral

Sunstone

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

Hardness: 6-6.5 on Mohs scale; Color: Orange, reddish-brown, or gold with a metallic shimmer; Luster: Vitreous to sub-metallic; Crystal Structure: Triclinic; Cleavage: Perfect in two directions; Specific Gravity: 2.62-2.72.

Hardness: 6-6
Color: Orange, reddish-brown, or gold with a metallic shimmer
Luster: Vitreous to sub-metallic

Identified March 18, 2026More mineral →

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Physical properties

Formation & geological history

Formed in igneous environments, typically in basaltic lava flows or pegmatites. The characteristic 'shiller' effect is caused by tiny inclusions of copper or hematite plates that reflect light as the rock solidifies from magma.

Uses & applications

Primarily used in the jewelry industry as a gemstone (cabochons or faceted stones) and for lapidary arts/collecting. High-quality Oregon Sunstone is a popular collector's item.

Geological facts

Also known as Aventurine Feldspar. It was once believed by Vikings to be a navigation tool (the 'Sunstone' legend) to find the sun through clouds, though scholars debate if they used this mineral or Calcite/Iolite.

Field identification & locations

Field identification is based on the 'aventurescence' (metallic glitter) and its characteristic salmon-to-orange color. Common locations include Oregon (USA), Norway, India, and Tanzania. To distinguish it from glass imitations, look for the natural cleavage planes and internal copper inclusions under a loupe.