gemstone

Almandine Garnet

Almandine (Fe3Al2(SiO4)3)

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

Hardness: 6

Identified August 4, 2026More gemstone →

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Physical properties

Formation & geological history

Forms in metamorphic rocks such as mica schists and gneisses via regional metamorphism, as well as in certain igneous rocks like granitic pegmatites.

Uses & applications

Used widely as a gemstone in jewelry, as an abrasive in waterjet cutting and sandblasting, and by mineral collectors.

Geological facts

Almandine is the most common and widespread species of the garnet group. Large, flawless specimens are often faceted into deep red gemstones known historically as carbuncles.

Field identification & locations

Can be identified by its deep red color, high specific gravity, lack of cleavage, and characteristic rounded crystal habit (dodecahedron or trapezohedron) often found embedded in metamorphic schists.