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

Sunstone

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

Hardness: 6.0-6.5 on Mohs scale. Color: Orange, red, or golden-brown with a metallic glitter (schiller). Luster: Vitreous to pearly. Crystal Structure: Triclinic. Cleavage: Perfect in two directions. Specific Gravity: 2.62-2.67.

Hardness
6
Luster
Vitreous to pearly
Identified More mineral

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Physical properties

Hardness: 6.0-6.5 on Mohs scale. Color: Orange, red, or golden-brown with a metallic glitter (schiller). 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 or andesitic lava flows. The unique glitter is caused by tiny inclusions of copper, hematite, or goethite that align during cooling.

Uses & applications

Used primarily as a gemstone for jewelry (beads, cabochons, or faceted) and collected as a mineral specimen.

Geological facts

The metallic 'glitter' is known as aventurescence. Oregon Sunstone is a famous variety that contains microscopic copper crystals, making it unique to that region.

Field identification & locations

Identify in the field by its distinct orange hue and 'flash' when rotated under light. Commonly found in Oregon (USA), Norway, Tanzania, and India. Look for feldspar-type cleavage planes.