Rock Identifier
Tumbled labradorite (Labradorite, a calcium-rich plagioclase feldspar; approximately (Ca,Na)(Al,Si)₄O₈) — mineral
mineral

Tumbled labradorite

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

AI-generated identification · may be incorrect

Hardness 6–6.5 Mohs; dark gray to blue-green with polished vitreous luster and possible blue-green schiller (labradorescence). It has triclinic crystal structure and two cleavage directions, though polishing obscures them.

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Physical properties

Hardness 6–6.5 Mohs; dark gray to blue-green with polished vitreous luster and possible blue-green schiller (labradorescence). It has triclinic crystal structure and two cleavage directions, though polishing obscures them.

Formation & geological history

Forms in slowly cooled mafic igneous rocks such as anorthosite, gabbro, and basaltic complexes, commonly during Precambrian to younger geological events. The specimens shown are human-polished and rounded.

Uses & applications

Used as ornamental stone, beads, cabochons, carvings, and collectible metaphysical specimens; rarely used as architectural stone.

Geological facts

Its characteristic flash results from light interference between microscopic feldspar lamellae produced during exsolution. Strong labradorescence is most visible when rotated under directional light.

Field identification & locations

Common sources include Madagascar, Finland, Canada, Norway, and Russia. Identify it by gray-green body color, feldspar-like cleavage, moderate hardness, and blue internal flashes; avoid confusing it with blue aventurine or dyed material.