mineral

Polished labradorite

Labradorite, calcium-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 color with gray-white patches and possible blue-green labradorescence; vitreous to pearly luster, triclinic crystal structure, two good cleavage directions. The pictured piece is polished and likely a cabochon.

Identified August 16, 2026More mineral →

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Physical properties

Formation & geological history

Forms in mafic igneous rocks such as basalt, gabbro, and anorthosite as magma cools; specimens commonly formed in Precambrian crystalline terranes, though labradorite occurs in rocks of many ages.

Uses & applications

Used for cabochons, beads, carvings, decorative stone, and architectural slabs; valued chiefly for strong blue or multicolor flash.

Geological facts

Its optical color play results from light interference in microscopic lamellae produced by exsolution within the feldspar crystal.

Field identification & locations

Identify by its dark feldspar appearance, blocky cleavage, hardness, and blue-green flash when rotated under directional light; major sources include Labrador, Canada, Madagascar, Finland, Norway, and Mexico.