gemstone

Tumbled garnet (probable almandine)

Almandine garnet, Fe₃Al₂(SiO₄)₃; visual identification is uncertain from the image

AI-generated identification · may be incorrect

Dark burgundy-purple to reddish brown, vitreous luster, granular/isotropic cubic crystal structure, and no cleavage; Mohs hardness 7–7.5, specific gravity about 3.9–4.3. The rounded shape and surface sheen indicate tumbling or polishing.

Identified August 20, 2026More gemstone →

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Physical properties

Formation & geological history

Garnets commonly form during regional or contact metamorphism of aluminum-rich rocks, though some occur in igneous rocks; almandine deposits range from Precambrian to recent geological ages. Common sources include India, Sri Lanka, Madagascar, the United States, and Brazil.

Uses & applications

Used as an abrasive and, when clear and attractive, as a gemstone in jewelry and mineral collections. Small opaque tumbled pieces are mainly sold as ornamental stones.

Geological facts

Garnet is a mineral-group name rather than one mineral species; almandine is the common iron-rich red member. Garnets typically lack cleavage and commonly form dodecahedral or trapezohedral crystals.

Field identification & locations

Identify by its wine-red color, high hardness, heft, glassy luster, and lack of cleavage; a strong magnet may weakly attract iron-rich almandine. The image is insufficient to exclude ruby, spinel, or dyed quartz.