mineral

Sunstone

Oligoclase (a variety of Plagioclase Feldspar) - (Na,Ca)(Si,Al)4O8

AI-generated identification · may be incorrect

Hardness: 6-6.5 (Mohs), Color: Orange, reddish-brown with metallic flashes (aventurescence), Luster: Vitreous to pearly, Crystal structure: Triclinic, Cleavage: Perfect in two directions

Hardness: 6-6

Identified May 16, 2026More mineral →

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Physical properties

Hardness: 6-6.5 (Mohs), Color: Orange, reddish-brown with metallic flashes (aventurescence), Luster: Vitreous to pearly, Crystal structure: Triclinic, Cleavage: Perfect in two directions

Formation & geological history

Forms in igneous rocks like basalt flows or plutonic rocks through the crystallization of magma. The characteristic metallic sheen is caused by tiny inclusions of hematite or copper particles.

Uses & applications

Primarily used as a gemstone in jewelry (cabochons or faceted stones) and as a lapidary material for carvings and metaphysical collecting.

Geological facts

The shimmering effect is known as adventurescence. In ancient folklore, some cultures believed sunstone contained the power of the sun and it was famously associated with Viking navigation (though often confused with Iceland Spar).

Field identification & locations

Identify by its distinct orange color and the internal sparkle or glittery effect when rotated under light. Major deposits are found in Oregon (USA), Norway, India, and Tanzania.