mineral

Garnet (Almandine)

Almandine (Fe3Al2(SiO4)3)

Hardness: 6.5-7.5. Color: Deep red, brownish-red to black. Luster: Vitreous to resinous. Crystal structure: Isometric (dodecahedral). Cleavage: None. Specific gravity: 3.5-4.3.

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

Identified July 9, 2026More mineral →

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Physical properties

Hardness: 6.5-7.5. Color: Deep red, brownish-red to black. Luster: Vitreous to resinous. Crystal structure: Isometric (dodecahedral). Cleavage: None. Specific gravity: 3.5-4.3.

Formation & geological history

Forms in regional metamorphic rocks such as mica schists and gneisses because of high pressure and temperature during mountain-building events. Can also be found in placer deposits due to its durability.

Uses & applications

Used primarily as an abrasive (sandblasting, sandpaper), for water jet cutting, as a semi-precious gemstone in jewelry, and as a geological proxy for pressure/temperature history.

Geological facts

Garnet is the birthstone for January. Almandine is the most common variety of the garnet group. Some garnets can show a four-rayed or six-rayed star effect known as asterism.

Field identification & locations

Look for its characteristic 12-sided (dodecahedral) or 24-sided (trapezohedral) crystal habit, its lack of cleavage, and its high hardness which allows it to scratch glass.