mineral

Polished labradorite cabochon

Labradorite, plagioclase feldspar; approximately (Ca,Na)(Al,Si)₄O₈

AI-generated identification · may be incorrect

Hardness 6–6.5 Mohs; gray to dark gray body with blue-green iridescent labradorescence, vitreous luster, triclinic crystal structure, and two good cleavage directions. The rounded, polished form is a cabochon, likely set in a small metal bezel.

Identified September 7, 2026More mineral →

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Physical properties

Formation & geological history

Forms in mafic igneous rocks such as basalt, gabbro, and anorthosite as calcium-rich plagioclase crystallizes from magma. Most gem-quality material is associated with Precambrian anorthosite deposits, especially in Madagascar, Finland, Canada, and Norway.

Uses & applications

Used for cabochon jewelry, carvings, ornamental objects, and mineral collecting; strong blue flash increases desirability.

Geological facts

Its shifting color is caused by light interference from microscopic lamellae produced during feldspar exsolution and cooling. The visible blue sheen is best seen by tilting the stone under directional light.

Field identification & locations

Identify by gray translucent body, broad internal cleavage-like fractures, and directional blue flash; distinguish from moonstone by its darker body and stronger multicolor sheen. Avoid ultrasonic cleaners and harsh impacts because of cleavage.