mineral

Almandine Garnet

Almandine - Fe3Al2(SiO4)3

Hardness: 7-7.5 (Mohs scale), Color: Deep red to reddish-brown/black, Luster: Vitreous to resinous, Crystal Structure: Isometric (Dodecahedral), Cleavage: None (indistinct), Specific Gravity: 4.1-4.3

Hardness: 7-7

Identified June 13, 2026More mineral →

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Physical properties

Hardness: 7-7.5 (Mohs scale), Color: Deep red to reddish-brown/black, Luster: Vitreous to resinous, Crystal Structure: Isometric (Dodecahedral), Cleavage: None (indistinct), Specific Gravity: 4.1-4.3

Formation & geological history

Formed in regionally metamorphosed rocks under high pressure and temperature, specifically in mica schists and gneisses. Also found as a primary mineral in some igneous rocks like granites.

Uses & applications

Abrasives (sandpaper, waterjet cutting), gemstones for jewelry, and indicators in geological research for determining metamorphic history.

Geological facts

Almandine is the most common member of the garnet group. The name is derived from Alabanda, an ancient city in Asia Minor where these stones were cut and polished in antiquity.

Field identification & locations

Identify in the field by its characteristic dodecahedral shape, reddish-brown color, and heavy weight (high density). Commonly found in metamorphic terrains such as the Adirondack Mountains (NY) or Idaho.