mineral

Almandine Garnet

Almandine (Fe3Al2Si3O12)

Hardness: 6.5-7.5 on the Mohs scale. Color: Deep red, brownish-red, or purplish-red. Luster: Vitreous to resinous. Crystal structure: Isometric (commonly dodecahedrons). Cleavage: None (conchoidal fracture). Specific Gravity: 4.1-4.3.

Hardness: 6
Color: Deep red, brownish-red, or purplish-red
Luster: Vitreous to resinous

Identified March 7, 2026More mineral →

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Physical properties

Formation & geological history

Formed primarily in metamorphic rocks such as mica schists and gneisses through the regional metamorphism of clay-rich sediments. They can also appear as detrital grains in river beds and beach sands due to their high resistance to weathering.

Uses & applications

Used widely as an industrial abrasive for waterjet cutting and sandblasting. High-quality transparent specimens are used as gemstones in jewelry. It is also the January birthstone.

Geological facts

Almandine is the most common variety of garnet. The name is a corruption of Alabanda, an ancient city in Asia Minor where these stones were historically cut and polished. Many 'deep red' gems found in historical crown jewels are actually Almandine garnets rather than rubies.

Field identification & locations

Identify in the field by the 'soccer ball' isometric crystal shapes (dodecahedrons), lack of cleavage, and high density. Commonly found in locations like Idaho (USA), India, Brazil, and Madagascar. Collectors look for well-defined crystal faces and light transparency.