Sunstone

Aventurine Feldspar (composition: (Ca,Na)((Al,Si)2Si2O8))

Rock Type: mineral

Sunstone

Physical Properties

Hardness: 6-6.5 (Mohs scale); Color: Orange, reddish-brown with internal metallic glitters; Luster: Vitreous to pearly; Crystal structure: Triclinic; Cleavage: Perfect in two directions; Specific Gravity: 2.62-2.67

Formation & Geological History

Formed in igneous environments, typically within basaltic lava flows or granitic pegmatites. The metallic 'schiller' effect is caused by tiny inclusions of copper, hematite, or goethite that precipitate during the cooling of the magma.

Uses & Applications

Primarily used as a gemstone for jewelry (rings, pendants, earrings) and as a collector's mineral specimen. Known for its aesthetic schiller effect.

Geological Facts

In 1987, Sunstone was designated the state gemstone of Oregon, USA. Ancient Viking legends suggest Sunstone may have been used as a navigation tool to find the sun through cloudy skies, though historians debate if they meant this specific mineral or Iceland Spar.

Field Identification & Locations

Identify by its 'aventurescence' (metallic glitter appearing under the surface when rotated). It is commonly found in Oregon (USA), Norway, Tanzania, India, and Russia. Collectors look for high copper content which increases the intensity of the 'sparkle'.

Identified on: 4/13/2026

Mode: Standard