mineral

Tumbled labradorite

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

AI-generated identification · may be incorrect

Typically gray to dark gray with a glassy luster and distinctive blue iridescent flash (labradorescence); Mohs hardness 6–6.5, triclinic crystal structure, two good cleavage directions, and specific gravity about 2.68–2.72.

Identified August 26, 2026More mineral →

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Physical properties

Formation & geological history

Forms in slowly cooled mafic igneous rocks such as gabbro, basalt, and anorthosite through crystallization of plagioclase feldspar. Major deposits are Precambrian, though labradorite occurs in rocks of several ages.

Uses & applications

Used as a cabochon, tumblestone, ornamental stone, and decorative facing material; it is also valued by mineral collectors.

Geological facts

Its blue flash results from light interference within microscopic lamellae produced by exsolution and twinning in the feldspar. The specimen appears polished and rounded, with visible blue labradorescence.

Field identification & locations

Identify it by gray body color, moderate hardness, feldspar cleavage, and changing blue sheen when rotated under a strong light; common sources include Labrador, Canada, Madagascar, Finland, Norway, and Russia.