mineral

Labradorite

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

Hardness: 6.0-6.5 on Mohs scale; Color: Gray to black base with iridescent colors (labradorescence) in blue, green, and gold; Luster: Vitreous to pearly; Crystal structure: Triclinic; Cleavage: Perfect in two directions.

Hardness: 6
Luster: Vitreous to pearly

Identified May 9, 2026More mineral →

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Physical properties

Formation & geological history

Formed in igneous environments, specifically mafic igneous rocks like basalt or gabbro, through the crystallization of magma. It is a calcium-enriched plagioclase feldspar. Common in Proterozoic anorthosite massifs about 1.2 billion years old.

Uses & applications

Widely used for cabochon jewelry, beads, and ornamental carvings. High-quality slabs are used for architectural counter tops, wall panelling, and flooring in luxury construction.

Geological facts

The iridescent play of color is caused by the interference of light within microscopic layers created by the exsolution of different feldspar phases as the mineral cooled. This effect is technically known as 'labradorescence'.

Field identification & locations

Identified by tilting the specimen to catch the flash of metallic-looking iridescent colors. Commonly found in Labrador (Canada), Madagascar, Finland (where it's called Spectrolite), and Norway. Look for the distinct cleavage planes and blue-green sheen.