mineral

Tumbled dark blue-green stone, likely labradorite or indigo gabbro

Indeterminate; possible feldspar-rich labradorite (plagioclase, NaAlSi₃O₈–CaAl₂Si₂O₈)

AI-generated identification · may be incorrect

Polished/tumbled, dark blue-green, vitreous to waxy luster; likely hardness 6–6.5 Mohs, with no visible cleavage in the rounded form. The image is insufficient to confirm crystal structure or specific gravity.

Identified August 11, 2026More mineral →

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Physical properties

Formation & geological history

If labradorite, it formed in slowly cooled mafic igneous rocks such as anorthosite or gabbro, commonly Precambrian in age. Blue color may reflect labradorescence from microscopic feldspar lamellae.

Uses & applications

Used as a lapidary stone, cabochon, bead, and ornamental object; not generally used in construction as an individual tumbled piece.

Geological facts

True labradorite commonly flashes blue, green, or gold when rotated under directional light. Uniformly dark material could instead be indigo gabbro, sodalite, dumortierite, or dyed stone.

Field identification & locations

Look for changing blue flashes, feldspar-like internal reflections, and hardness sufficient to scratch glass; streak, translucency, and a refractive-index or specific-gravity test would help. Common sources include Madagascar, Finland, Canada, and Norway.