Labradorite-bearing rough stone (tentative)

Gray-green, dull to vitreous luster with granular texture and apparent reflective feldspar surfaces; hardness about 6–6.5 Mohs, imperfect cleavage, triclinic crystal structure, and specific gravity around 2.68–2.75. The image alone cannot confirm composition, and the specimen may instead be weathered basalt or another feldspathic rock.

Labradorite crystallizes from cooling basaltic to gabbroic magma, commonly in Precambrian anorthosite and mafic igneous bodies. Its geological age depends on locality, ranging from Precambrian to younger igneous formations.

Used as a decorative stone, cabochon gemstone, lapidary material, and crushed aggregate; strongly iridescent material has collector value.

Its characteristic blue, green, or gold flash—labradorescence—comes from light interference within closely spaced feldspar lamellae. No obvious flash is visible here, possibly because the surface is weathered or the lighting is unfavorable.

Commonly found in Canada, Madagascar, Finland, Norway, Russia, and the United States. Look for gray feldspar with a colorful directional flash; a hardness, cleavage, and polished-surface test would help confirm it.