mineral

Polished labradorite fragment

Labradorite, a calcium-rich plagioclase feldspar; approximate formula (Ca,Na)(Al,Si)₄O₈

AI-generated identification · may be incorrect

Typically gray to blue-gray with blue-green iridescent flashes (labradorescence), vitreous luster, and a feldspar cleavage; Mohs hardness 6–6.5, specific gravity about 2.68–2.72. The image appears to show a small polished or naturally fractured fragment.

Identified August 15, 2026More mineral →

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Physical properties

Formation & geological history

Forms in slowly cooled mafic igneous rocks such as gabbro, anorthosite, and basalt, through crystallization of plagioclase feldspar. Most specimens formed during Precambrian to younger intrusive events, depending on locality.

Uses & applications

Used as ornamental stone, cabochons, beads, carvings, countertops, and decorative facing material; prized in jewelry for its color flash.

Geological facts

Its optical sheen results from light interference between microscopic lamellae of different plagioclase compositions, not from surface coating.

Field identification & locations

Identify it by gray body color, strong directional blue flash, feldspar cleavage, and hardness that scratches glass. Important sources include Madagascar, Finland, Canada, Norway, and Russia.