mineral

Labradorite

Labradorite (Plagioclase Feldspar Series) - (Ca, Na)(Al, Si)4O8

AI-generated identification · may be incorrect

Hardness: 6.0-6.5 on the Mohs scale. Color: Dark gray to gray-black body color with a characteristic iridescent play of color (blue, green, gold). Luster: Vitreous to pearly. Crystal system: Triclinic. Specific gravity: 2.68 to 2.72.

Hardness: 6
Luster: Vitreous to pearly

Identified March 25, 2026More mineral →

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Physical properties

Formation & geological history

Formed in mafic igneous rocks such as basalt and gabbro, and in anorthosite. It is a calcium-rich member of the plagioclase feldspar group, crystallizing from cooling magma. Most high-quality specimens date back to the Proterozoic era.

Uses & applications

Used primarily as a gemstone for jewelry, cabochons, and decorative carvings. Industrial uses include architectural stone, countertops, and floor tiles (often termed 'Blue Pearl' granite in the trade).

Geological facts

Famous for an optical phenomenon called labradorescence, which is caused by light diffracting within submicroscopic layers of exsolution lamellae (alternating layers of different feldspar compositions). Legend says the Northern Lights were once trapped in rocks on the coast of Labrador until an Inuit warrior freed them.

Field identification & locations

Identify in the field by rotating the specimen in light to see the metallic 'flash' or schiller effect. Commonly found in Canada (Labrador), Madagascar, Norway, and Finland (where a specific variety called Spectrolite is found).