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

Almandine Garnet

Almandine, Fe3Al2(SiO4)3

Hardness: 6.5 to 7.5 on the Mohs scale; Color: Dark red, brownish-red, or nearly black; Luster: Vitreous to resinous; Crystal Structure: Isometric (cubic), commonly forming dodecahedrons or trapezohedrons; Cleavage: None (conchoidal fracture); Specific Gravity: 3.9 to 4.3

Hardness
6
Color
Dark red, brownish-red, or nearly black
Luster
Vitreous to resinous
Identified More mineral
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Physical properties

Hardness: 6.5 to 7.5 on the Mohs scale; Color: Dark red, brownish-red, or nearly black; Luster: Vitreous to resinous; Crystal Structure: Isometric (cubic), commonly forming dodecahedrons or trapezohedrons; Cleavage: None (conchoidal fracture); Specific Gravity: 3.9 to 4.3

Formation & geological history

Forms primarily in metamorphic rocks such as mica schists and gneisses through regional metamorphism of aluminum-rich argillaceous sediments, and also in certain igneous rocks like granitic pegmatites.

Uses & applications

Used widely as a gemstone in jewelry, as an abrasive in sandblasting and waterjet cutting, and in industrial water filtration.

Geological facts

Almandine is the most common variety of garnet and is named after the ancient town of Alabanda in Asia Minor where cut and polished stones were traded in antiquity.

Field identification & locations

Can be identified in the field by its characteristic dark red color, lack of cleavage, high hardness, and tendency to form rounded crystal habits or rhombic dodecahedrons within metamorphic host rocks. Found globally, notably in India, Brazil, Madagascar, and the United States.