mineral

Labradorite

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

Hardness: 6-6.5; Color: Dark grey to black with blue, green, and gold iridescent flashes; 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 9, 2026More mineral →

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Physical properties

Formation & geological history

Forms in mafic igneous rocks such as basalt and gabbro, as well as in anorthosites. It is created as molten rock cools and minerals crystallize, specifically within the plagioclase feldspar series.

Uses & applications

Primarily used in jewelry for its labradorescence, as well as in decorative items, interior design (countertops), and as a collector's specimen.

Geological facts

The optical effect 'labradorescence' is caused by internal fractures or lamellar twinning that reflect light back and forth, creating a spectral play of colors. It was first discovered in Labrador, Canada, in 1770.

Field identification & locations

To identify in the field, look for a dark, dull rock that displays vibrant iridescent colors (blue, green, yellow) when tilted towards the light. It is commonly found in Canada, Madagascar, Norway, and Finland (where a specific variety called Spectrolite is found).