mineral

Almandine Garnet

Almandine (Fe3Al2Si3O12)

Hardness: 7.5-8.5 Mohs scale; Color: Deep red, reddish-brown, or black; Luster: Vitreous to resinous; Crystal structure: Isometric; Cleavage: None (conchoidal fracture); Specific gravity: 4.1-4.3

Hardness: 7
Color: Deep red, reddish-brown, or black
Luster: Vitreous to resinous

Identified March 16, 2026More mineral →

Identify your own rocks.

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

App Store Google Play

Physical properties

Hardness: 7.5-8.5 Mohs scale; Color: Deep red, reddish-brown, or black; Luster: Vitreous to resinous; Crystal structure: Isometric; Cleavage: None (conchoidal fracture); Specific gravity: 4.1-4.3

Formation & geological history

Formed in regional metamorphic rocks such as mica schists and gneisses through the metamorphosis of clay-rich sedimentary rocks. They can range from the Proterozoic to Cenozoic eras.

Uses & applications

Commonly used as gemstones in jewelry. Industrial applications include abrasives for waterjet cutting and sandblasting due to its high hardness.

Geological facts

Almandine is the most common member of the garnet group. Some specimens exhibit 'asterism,' a four-rayed star effect when cut as cabochons. It has been used since ancient Roman times.

Field identification & locations

Identify in the field by its dodecahedral (12-sided) crystal habit and its high density compared to surrounding rock. Found globally, with major deposits in India, Brazil, and the USA (New York/Idaho).