mineral

Garnet

Almandine formula: Fe3Al2(SiO4)3

Hardness: 6.5-7.5 on Mohs scale. Color: Deep red to reddish-purple. Luster: Vitreous to resinous. Crystal structure: Isometric (often dodecahedral). Cleavage: None (conchoidal fracture). Specific gravity: 3.5-4.3.

Hardness: 6
Color: Deep red to reddish-purple
Luster: Vitreous to resinous

Identified March 15, 2026More mineral →

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Physical properties

Formation & geological history

Formed most commonly in metamorphic rocks such as mica schist or gneiss during high-pressure and high-temperature regional metamorphism. Can also be found in igneous rocks like pegmatites.

Uses & applications

Used widely as a gemstone in jewelry. In industry, it is used as an abrasive in sandblasting, waterjet cutting, and for water filtration media due to its hardness and angular fracture.

Geological facts

Garnets have been used as gemstones and abrasives since the Bronze Age. While red is most common, garnets actually occur in every color except pure blue. It is the birthstone for January.

Field identification & locations

Identify in the field by its characteristic red color and glassy, fractured appearance in host rock. It frequently forms distinct, rounder 'grains' compared to surrounding minerals. Common locations include New York, Idaho, India, and Brazil.