mineral

Polished labradorite cabochon

Labradorite, calcium-sodium feldspar (approximately (Ca,Na)(Al,Si)₄O₈)

AI-generated identification · may be incorrect

Hardness 6–6.5 Mohs; gray-green to brown body color with vivid blue-green labradorescence, vitreous luster, triclinic crystal structure, and two good cleavage directions. The smooth oval form is a polished cabochon.

Identified August 28, 2026More mineral →

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Physical properties

Formation & geological history

Forms in mafic igneous rocks such as basalt, gabbro, and anorthosite as slowly cooled feldspar; much material is Precambrian, though exact age depends on locality. Optical color flashes arise from light interference between microscopic feldspar lamellae.

Uses & applications

Used in cabochon jewelry, ornamental objects, and mineral collections. Commercial value depends strongly on flash intensity, coverage, and color.

Geological facts

The blue flash is called labradorescence, not ordinary surface paint or iridescence. Strong blue specimens are especially sought after.

Field identification & locations

Identify it by its gray base and shifting blue flash when tilted under directional light; it is commonly sourced from Madagascar, Finland, Canada, Norway, and Russia. Avoid harsh impacts because feldspar cleavage can cause chipping.