mineral

Almandine Garnet

Almandine, Fe3Al2(SiO4)3

Hardness: 6.5–7.5 Mohs; Color: Deep red, brownish-red to black; Luster: Vitreous to resinous; Crystal structure: Cubic (dodecahedral); Cleavage: Indistinct; Specific Gravity: 3.9–4.3

Hardness: 6
Color: Deep red, brownish-red to black
Luster: Vitreous to resinous

Identified April 29, 2026More mineral →

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Physical properties

Hardness: 6.5–7.5 Mohs; Color: Deep red, brownish-red to black; Luster: Vitreous to resinous; Crystal structure: Cubic (dodecahedral); Cleavage: Indistinct; Specific Gravity: 3.9–4.3

Formation & geological history

Formed through regional metamorphism of argillaceous sediments. Found in metamorphic rocks such as mica schists, where high pressure and temperature facilitate crystal growth.

Uses & applications

Used as an industrial abrasive (sandpaper, waterjet cutting), a gemstone in jewelry, and a geological index mineral for determining metamorphic grade.

Geological facts

Almandine is the most common member of the garnet group. It has been used in jewelry since the time of Ancient Rome and was particularly popular in Victorian 'Bohemian garnet' jewelry.

Field identification & locations

Identify by its deep red color and dodecahedral crystal habit. Often found in river gravels or embedded in silver-grey mica schist. Hardness helps differentiate it from softer red minerals like ruby.