Labradorite

Physical Properties

Hardness: 6.0-6.5 (Mohs scale); Color: Typically grey-green, dark grey, or black with iridescent flashes (labradorescence); Luster: Vitreous to pearly; Crystal structure: Triclinic; Cleavage: Perfect in two directions; Specific gravity: 2.68-2.72

Formation & Geological History

Formed as an intermediate to calcic member of the plagioclase series in igneous rocks like basalt and norite. It crystallizes from cooling magma, often in deep-seated plutonic environments.

Uses & Applications

Primarily used as a gemstone in jewelry (cabochons, beads) and as a decorative stone for counter tops, tiles, and carvings.

Geological Facts

It is named after its discovery site in Labrador, Canada in 1770. The play of color, called labradorescence, is caused by internal lamellar structures that diffract light (Rayleigh scattering).

Field Identification & Locations

Identify by rotating it in the light to see metallic blue, green, or gold flashes against a dull gray background. Common locations include Canada, Madagascar, Finland (Spectrolite), and Russia.

Identified on: 4/22/2026

Mode: Standard