mineral
Tumbled blue-gray mineral specimen, likely labradorite
Labradorite, a calcium-rich plagioclase feldspar; approximate formula (Ca,Na)(Al,Si)₄O₈
AI-generated identification · may be incorrectHardness 6–6.5 Mohs; blue-gray body color with possible blue-green iridescent sheen, vitreous to pearly luster, triclinic crystal structure, and two good cleavage directions. The rounded, glossy form indicates tumbling and polishing.
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Physical properties
Hardness 6–6.5 Mohs; blue-gray body color with possible blue-green iridescent sheen, vitreous to pearly luster, triclinic crystal structure, and two good cleavage directions. The rounded, glossy form indicates tumbling and polishing.
Formation & geological history
Labradorite crystallizes from cooling mafic igneous rocks such as basalt, gabbro, and anorthosite, commonly in Precambrian terrains. The specimen’s exact age and locality cannot be determined from the image.
Uses & applications
Used as a decorative stone, carvings, cabochons, jewelry, countertops, and mineral-collection specimens.
Geological facts
Its characteristic color flashes, called labradorescence, result from light interference within microscopic exsolution layers in the feldspar. Strong blue or multicolor flashes generally increase desirability.
Field identification & locations
Identify it by gray translucent-to-opaque feldspar, hardness near 6, cleavage, and changing blue flashes when rotated under a light; common sources include Madagascar, Finland, Canada, Norway, and Mexico.
