mineral

Garnet

Almandine (Fe3Al2(SiO4)3)

Hardness: 6.5-7.5 (Mohs), Color: Deep red to reddish-brown, Luster: Vitreous to resinous, Crystal Structure: Isometric/Dodecahedral, Cleavage: Indistinct/No true cleavage, Specific Gravity: 3.5-4.3

Hardness: 6

Identified June 14, 2026More mineral →

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Physical properties

Hardness: 6.5-7.5 (Mohs), Color: Deep red to reddish-brown, Luster: Vitreous to resinous, Crystal Structure: Isometric/Dodecahedral, Cleavage: Indistinct/No true cleavage, Specific Gravity: 3.5-4.3

Formation & geological history

Formed under high-pressure and high-temperature conditions typically in metamorphic rocks like schist or gneiss. These often weather out of the host rock and accumulate as alluvial pebbles in stream beds.

Uses & applications

Used as an abrasive in sandpaper and waterjet cutting, as a gemstone for jewelry (January birthstone), and as a mineral specimen for collectors.

Geological facts

Almandine is the most common member of the garnet group. It is sometimes known as 'Carbuncle' in historic jewelry. It was widely used in ancient Roman signet rings.

Field identification & locations

Identify by the characteristic reddish-purplish hue, high density for its size, and 'soccer ball' shape if crystal faces are present. Commonly found in metamorphic terrains and river gravels.