mineral
Labradorite rough
Labradorite, a calcium-rich plagioclase feldspar (approximately (Ca,Na)(Al,Si)₄O₈)
AI-generated identification · may be incorrectDark gray to black, vitreous to pearly luster, commonly displaying blue-green iridescent labradorescence; Mohs hardness 6–6.5, triclinic crystal structure, and two good cleavage directions. The pictured blue flashes strongly suggest labradorite, though lighting can exaggerate the effect.
Identified More mineral →
Explore Labradorite rough in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Dark gray to black, vitreous to pearly luster, commonly displaying blue-green iridescent labradorescence; Mohs hardness 6–6.5, triclinic crystal structure, and two good cleavage directions. The pictured blue flashes strongly suggest labradorite, though lighting can exaggerate the effect.
Formation & geological history
Forms in slowly cooled mafic igneous rocks such as basalt, gabbro, and anorthosite; many gem-quality specimens come from Madagascar, Finland, Canada, and Norway. Its age depends on locality, ranging from ancient Precambrian deposits to younger igneous bodies.
Uses & applications
Used as a decorative and architectural stone, carved objects, cabochons, and collector specimens; gem-quality material is popular in jewelry.
Geological facts
Labradorescence results from light interference within microscopic exsolution layers in the feldspar. Spectrolite is the trade name for especially vivid Finnish labradorite.
Field identification & locations
Identify it by its dark body color, relatively soft feldspar hardness, cleavage, and shifting blue, green, gold, or orange flashes when rotated. Avoid confusing it with obsidian, which lacks cleavage and typically has a glassier fracture.
