mineral

Sunstone

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

AI-generated identification · may be incorrect

Hardness: 6-6.5 (Mohs scale); Color: Brownish-red to orange; Luster: Vitreous to pearly; Crystal structure: Triclinic; Cleavage: Perfect in two directions; Schiller effect (aventurescence) caused by hematite or copper inclusions.

Hardness: 6-6
Color: Brownish-red to orange
Luster: Vitreous to pearly

Identified July 4, 2026More mineral →

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Physical properties

Formation & geological history

Formed in igneous environments, typically in lava flows such as basalt or in pegmatites. The characteristic glitter comes from metal inclusions that crystallize as the magma cools and solidifies.

Uses & applications

Primarily used as a gemstone in jewelry (rings, pendants, beads) and for metaphysical or decorative collecting.

Geological facts

The metallic glitter seen in this specimen is known as 'aventurescence', caused by light reflecting off tiny platelets of hematite, goethite, or copper. Oregon in the United States is famous for producing high-quality specimens, some containing rare copper inclusions.

Field identification & locations

Identify by its unique 'sparkle' or 'glow' within the stone when rotated under light. Look for the characteristic cleavage planes of feldspar. Found in Norway, Tanzania, India, and the United States (Oregon).