Sunstone

Hardness: 6-6.5 (Mohs scale), Color: Orange/Reddish-brown with golden or copper-tinted metallic reflections (schiller effect), Luster: Vitreous to sub-vitreous, Crystal structure: Triclinic, Cleavage: Perfect in two directions.

Formed in igneous environments, typically within basalt or andesite lava flows. The unique coloring and sparkle come from tiny inclusions of hematite or copper (in the case of Oregon Sunstone).

Primarily used as a gemstone for jewelry (rings, pendants) and as a collector's mineral specimen. Some lower grade material is used for ornamental carvings.

The metallic 'glitter' in sunstone is known as aventurescence. Oregon Sunstone is a famous variety and is the official state gemstone of Oregon, USA. Ancient Vikings purportedly used sunstone (calcite or cordierite/iolite) as a navigation tool, though the trade name 'Sunstone' today refers to the feldspar variety seen here.

Identify in the field by its distinct orange hue and characteristic metallic reflections when tilted in the light. Often found in volcanic areas such as the high desert of Oregon, southern Norway, and India.