metamorphic
Almandine Garnet
Almandine (Fe3Al2(SiO4)3)
Hardness: 7-7.5 (Mohs scale); Color: Deep brownish-red to black; Luster: Vitreous to resinous; Crystal structure: Isometric (dodecahedral); Cleavage: None; Specific gravity: 4.31
- Hardness
- 7-7
- Color
- Deep brownish-red to black
- Luster
- Vitreous to resinous
Identified More metamorphic →
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Physical properties
Hardness: 7-7.5 (Mohs scale); Color: Deep brownish-red to black; Luster: Vitreous to resinous; Crystal structure: Isometric (dodecahedral); Cleavage: None; Specific gravity: 4.31
Formation & geological history
Forms during regional metamorphism of clay-rich sedimentary rocks like shale, commonly found in mica schists and gneisses.
Uses & applications
Used primarily as an abrasive in sandblasting and water-jet cutting; high-quality specimens are used in jewelry.
Geological facts
Almandine is the most common member of the garnet group. The name is a corruption of Alabanda, a city in Asia Minor where these stones were historically cut.
Field identification & locations
Identify in the field by its characteristic dodecahedral crystal shape and extreme hardness. Often found as porphyroblasts in metamorphic schists in locations like the Adirondack Mountains or the Alps.
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