mineral

Tumbled labradorite

Labradorite, a calcium-rich plagioclase feldspar (approximately NaAlSi₃O₈–CaAl₂Si₂O₈)

AI-generated identification · may be incorrect

Typically gray to blue-gray with blue-green iridescent labradorescence, vitreous luster, hardness 6–6.5 Mohs, and a triclinic crystal structure with two good cleavages. The rounded, glossy surface indicates tumbling and may obscure cleavage.

Identified August 21, 2026More mineral →

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Physical properties

Formation & geological history

Forms in mafic igneous rocks such as basalt, gabbro, and anorthosite when plagioclase crystallizes from magma; most commercial material comes from Madagascar, Finland, Canada, and Norway. The specimen’s exact age cannot be determined visually.

Uses & applications

Used as a cabochon, tumbled stone, bead, ornamental object, and collector specimen; large labradorite slabs are used decoratively in interiors.

Geological facts

Its blue flash is caused by light interference from microscopic exsolution lamellae within the feldspar. Strong labradorescence is more valuable than plain gray material.

Field identification & locations

Identify by the gray body color, distinctive moving blue flash, feldspar-like hardness, and lack of glassy transparency; rotate it under directional light to see the effect. Avoid confusing it with moonstone or dyed stones.