Labradorite

Physical Properties

Hardness: 6.0-6.5 Mohs; Color: Gray-green with blue/yellow/green iridescence; Luster: Vitreous to pearly; Crystal structure: Triclinic; Cleavage: Perfect in two directions; Specific gravity: 2.68-2.72

Formation & Geological History

Formed in igneous environments (mafic rocks like basalt or gabbro) or metamorphic rocks. It develops its characteristic iridescence through lamellar twinning or exsolution during cooling. Key deposits date back to the Proterozoic Era.

Uses & Applications

Commonly used in jewelry as cabochons, as ornamental stone for countertops and tiles, and as a popular specimen for crystal healing and mineral collectors.

Geological Facts

The iridescent optical effect is known as 'labradorescence,' caused by light diffracting within sub-microscopic layers of different feldspar compositions. It was first discovered in Labrador, Canada in 1770.

Field Identification & Locations

Identify by rotating under light to catch the sudden 'flash' of color (schiller). In the field, look for a gray, unremarkable rock that reveals bright blue or gold flashes on cleavage planes. Major sources include Canada, Madagascar, and Finland (Spectrolite).

Identified on: 4/21/2026

Mode: Standard