mineral
Polished labradorite-bearing rock
Labradorite, a calcium-rich plagioclase feldspar; likely mixed with quartz and mafic minerals
AI-generated identification · may be incorrectHardness about 6–6.5 Mohs; gray, brown, blue-green, and golden patches with vitreous to pearly luster and visible labradorescent flashes. Plagioclase has triclinic crystals and two good cleavage directions; exact composition is uncertain from the photo.
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Physical properties
Hardness about 6–6.5 Mohs; gray, brown, blue-green, and golden patches with vitreous to pearly luster and visible labradorescent flashes. Plagioclase has triclinic crystals and two good cleavage directions; exact composition is uncertain from the photo.
Formation & geological history
Labradorite crystallizes in cooling mafic igneous rocks such as basalt, gabbro, and anorthosite, generally during Precambrian to younger intrusive events. The specimen appears tumbled or polished, enhancing its sheen and color play.
Uses & applications
Used as an ornamental stone, countertops, carvings, cabochons, and collectible mineral specimens; it has limited industrial value compared with ordinary feldspar.
Geological facts
Its blue or gold iridescence, called labradorescence, results from light interference in thinly exsolved feldspar layers rather than surface paint. Similar-looking polished stones may be larvikite or mixed feldspar.
Field identification & locations
Look for gray feldspar, prominent cleavage, hardness near 6, and angular blue-green or gold flashes when rotated under light; common sources include Labrador, Canada, Madagascar, Finland, and Norway.
