mineral

Labradorite

Labradorite (Ca, Na)(Al, Si)4O8

Hardness: 6-6.5; Color: Dark gray to gray-black with iridescent play of color (labradorescence) in blue, green, and gold; Luster: Vitreous to pearly; Crystal structure: Triclinic; Cleavage: Two directions at nearly 90 degrees; Specific gravity: 2.68-2.72.

Hardness: 6-6
Luster: Vitreous to pearly

Identified May 30, 2026More mineral →

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Physical properties

Formation & geological history

Forms in mafic igneous rocks such as basalt, gabbro, and norite. It crystallizes from cooling magma in plutonic environments. Notable deposits range from the Proterozoic to more recent geological eras.

Uses & applications

Primarily used as a gemstone in jewelry, ornamental carvings, and high-end architectural countertops or floor tiles.

Geological facts

The iridescent effect called 'labradorescence' is caused by light reflecting off microscopically thin layers of different plagioclase feldspars (albite and anorthite) within the stone. It was first discovered on Paul's Island near Nain, Labrador, Canada in 1770.

Field identification & locations

Identify in the field by rotating the specimen to look for the 'flash' of blue or green color against a dull gray body. It is commonly found in Labrador (Canada), Finland, Madagascar, and Russia. Look for twins or cleavage planes that catch the light.