mineral

Polished labradorite

Labradorite, Ca-rich plagioclase feldspar; approximately (Ca,Na)(Al,Si)₄O₈

AI-generated identification · may be incorrect

Hardness 6–6.5 Mohs; dark gray to black body, vitreous luster, triclinic crystal structure, two good cleavage directions, and distinctive blue-green iridescence (labradorescence). The rounded form is tumbled or polished.

Identified August 20, 2026More mineral →

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Physical properties

Formation & geological history

Forms as an igneous plagioclase feldspar in basaltic to anorthositic rocks, where microscopic lamellae produce optical color flashes; most specimens are Precambrian to younger. Major sources include Madagascar, Finland, Canada, Norway, and Russia.

Uses & applications

Used for cabochons, beads, carvings, ornamental objects, and collector specimens; occasionally marketed as decorative architectural stone.

Geological facts

Labradorescence results from light interference between compositionally distinct feldspar layers, not surface paint or metallic inclusions.

Field identification & locations

Identify it by rotating the stone under light: blue, green, gold, or multicolor flashes appear against a gray-black base, and it is softer than quartz. Value depends strongly on flash coverage, color, polish, size, and locality.