Rock Identifier
Polished labradorite cabochon (Labradorite, calcium-rich plagioclase feldspar; approximately (Ca,Na)(Al,Si)₄O₈) — mineral
mineral

Polished labradorite cabochon

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

AI-generated identification · may be incorrect

Typically gray to greenish-gray with blue-green iridescent labradorescence, a vitreous luster, and triclinic crystal structure; hardness 6–6.5 Mohs, specific gravity about 2.68–2.72, with two good cleavage directions. The rounded, polished form is a cabochon.

Identified More mineral
Explore Polished labradorite cabochon in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

Physical properties

Typically gray to greenish-gray with blue-green iridescent labradorescence, a vitreous luster, and triclinic crystal structure; hardness 6–6.5 Mohs, specific gravity about 2.68–2.72, with two good cleavage directions. The rounded, polished form is a cabochon.

Formation & geological history

Forms in slowly cooled mafic igneous rocks such as basalt, gabbro, and anorthosite through crystallization of plagioclase feldspar. Major deposits occur in Madagascar, Finland, Canada, Norway, and Mexico; individual crystals commonly formed in Precambrian to younger igneous bodies.

Uses & applications

Used for cabochons, beads, carvings, and ornamental objects; also occurs as a rock-forming mineral in construction stone. Jewelry value depends strongly on the intensity and coverage of its flash.

Geological facts

Its shifting colors result from light interference in microscopic lamellae produced by exsolution within the feldspar. Strong blue, green, or multicolor flashes are especially desirable.

Field identification & locations

Identify it by gray body color, feldspar cleavage, moderate hardness, and moving blue-green flash when tilted under directional light; do not confuse it with moonstone or synthetic glass. The pictured specimen appears polished and likely small.