Rock Identifier
Garnet (likely Almandine) (Almandine Garnet, Fe3Al2(SiO4)3) — mineral
mineral

Garnet (likely Almandine)

Almandine Garnet, Fe3Al2(SiO4)3

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

Hardness
6
Color
Deep red to brownish-red
Luster
Vitreous to resinous
Identified More mineral

Identify your own rocks.

Get a report just like this from any photo, free.

Physical properties

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

Formation & geological history

Formed under high-pressure and high-temperature conditions during regional metamorphism of clay-rich sedimentary rocks (shales). Often found in metamorphic schists and gneisses, or as detrital grains in river sands.

Uses & applications

Used primarily in jewelry as a gemstone and in industry as an abrasive (sandpaper, waterjet cutting) due to its hardness and lack of cleavage.

Geological facts

Garnets have been used as gemstones since the Bronze Age. The name 'garnet' comes from the Latin 'granatus' (grain/seed), likely referencing its resemblance to pomegranate seeds. It is the birthstone for January.

Field identification & locations

Identify in the field by its distinct 12-sided (dodecahedral) or 24-sided (trapezohedral) crystal shape, deep red color, and lack of cleavage. Common locations include New York (USA), India, Brazil, and Madagascar.