Mineral

Garnet (Almandine)

Almandine (Fe3Al2(SiO4)3)

Hardness: 6.5-7.5 on Mohs scale; Color: Deep red, reddish-brown, or purplish-black; Luster: Vitreous to resinous; Crystal structure: Isometric (often dodecahedral); Cleavage: None (conchoidal fracture); Specific Gravity: 3.5-4.3

Hardness: 6
Color: Deep red, reddish-brown, or purplish-black
Luster: Vitreous to resinous

Identified March 11, 2026More mineral →

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Physical properties

Formation & geological history

Formed through regional metamorphism of clay-rich sedimentary rocks like shale, creating mica schists and gneisses. They are found in metamorphic belts worldwide, ranging from Precambrian to Cenozoic age.

Uses & applications

Used as an industrial abrasive (sandblasting, waterjet cutting), in sandpaper, and as a gemstone. High-quality transparent specimens are used in jewelry, while rough specimens are popular for mineral collecting.

Geological facts

Garnet is the birthstone for January. Almandine is the most common member of the garnet group and is often referred to as 'precious garnet' when it reaches gem quality. Large crystals are sometimes called 'Iron garnets'.

Field identification & locations

Identify in the field by its characteristic 12-sided (dodecahedral) shape, high hardness (will scratch glass), and dark red translucent edges when held to a light. Commonly found in schist outcrops or as weathered stones in creek beds.