Labradorite

Physical Properties

Hardness: 6-6.5 (Mohs scale), Color: Dark grey to green-black with labradorescence (blue, green, yellow, gold flashes), Luster: Vitreous to pearly, Crystal structure: Triclinic, Cleavage: Perfect in two directions.

Formation & Geological History

Formed in mafic igneous rocks such as basalt or gabbro through crystallization from cooling magma. Often found in anorthosite massifs. Mostly Proterozoic to Phanerozoic in age.

Uses & Applications

Primarily used as a gemstone for jewelry, ornamental carvings, and high-end construction countertops. Highly valued by collectors for its optical effects.

Geological Facts

The iridescent optical effect is called 'labradorescence,' caused by internal light scattering from submicroscopic exsolution lamellae within the crystal structure. It was first discovered in Labrador, Canada.

Field Identification & Locations

Identify by rotating under a light source to find the shifting color 'flash.' Common locations include Canada (Labrador), Madagascar, Norway, and Finland. Look for a dark, metallic luster that suddenly reveals bright colors.

Identified on: 5/18/2026

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