mineral

Polished labradorite

Labradorite, calcium-rich plagioclase feldspar (approximately Ca0.5–0.7Na0.5–0.3Al1.5–1.7Si2.5–2.3O8)

AI-generated identification · may be incorrect

Hardness 6–6.5 Mohs; gray-brown body color with blue-green iridescent flash (labradorescence), vitreous luster, triclinic crystal structure, and two good cleavage directions. The rounded shape indicates tumbling or polishing.

Identified August 11, 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; many gem-quality examples formed in Precambrian anorthosite complexes. Major sources include Madagascar, Finland, Canada, Norway, and Russia.

Uses & applications

Used for cabochons, beads, carvings, polished stones, and ornamental countertops; valued more for strong, broad blue or multicolor flash than for transparency.

Geological facts

Its iridescence results from light interference in thin, compositionally layered lamellae produced during feldspar exsolution. Spectrolite is the particularly vivid Finnish variety.

Field identification & locations

Identify by gray base color, feldspar-like cleavage, and directional blue flash that changes as the stone moves; a glassy imitation lacks natural cleavage and internal lamellar effects. The pictured specimen appears tumbled and polished.