mineral

Likely polished labradorite or black-and-white feldspar specimen

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

AI-generated identification · may be incorrect

Dark gray to black with abundant pale reflective flashes or mottling; vitreous to pearly luster, triclinic crystal structure, two cleavage directions, and Mohs hardness 6–6.5. The photo is too dark for certain identification; it could also be a polished gabbro or another feldspar-rich rock.

Identified August 23, 2026More mineral →

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Physical properties

Formation & geological history

Labradorite crystallizes from slowly cooling mafic igneous magma, commonly in gabbro, anorthosite, and basalt; major deposits formed in Precambrian intrusive complexes. Its blue, green, or silver iridescence results from light interference within feldspar lamellae.

Uses & applications

Used as a decorative stone, cabochon, carving material, countertops, and collectible mineral specimens. Strong iridescence increases jewelry and display value.

Geological facts

Its characteristic color play is called labradorescence, caused by nanoscale intergrowths in the feldspar. It is commonly confused with larvikite, which has similar blue-gray flashes.

Field identification & locations

Look for feldspar cleavage, moderate hardness, and angular blue/silver flashes that change with viewing angle; a glass-scratch test and fresh cleavage surface help distinguish it from glass. Common sources include Canada, Madagascar, Finland, Norway, and Mexico.