metamorphic
Garnet in Matrix
Almandine Garnet (Fe3Al2(SiO4)3)
Hardness: 6.5-8.5 on Mohs scale; Color: Deep red to brownish-red; Luster: Vitreous to resinous; Crystal structure: Isometric/Isometric-hexoctahedral; Specific Gravity: 3.5-4.3.
- Hardness
- 6
- Color
- Deep red to brownish-red
- Luster
- Vitreous to resinous
Identified More metamorphic →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6.5-8.5 on Mohs scale; Color: Deep red to brownish-red; Luster: Vitreous to resinous; Crystal structure: Isometric/Isometric-hexoctahedral; Specific Gravity: 3.5-4.3.
Formation & geological history
Formed during regional metamorphism of clay-rich sedimentary rocks (like shale) under high pressure and temperature conditions. Typically found in mica schists or gneisses.
Uses & applications
Mainly used as an abrasive in sandblasting and waterjet cutting; high-quality specimens are used as gemstones in jewelry and as mineral specimens for collectors.
Geological facts
Garnets are known for their 'dodecahedron' crystal shape. Almandine is the most common member of the garnet group and has been used as a gemstone for thousands of years, notably by Ancient Romans.
Field identification & locations
Identify in the field by looking for hard, rounded, or 12-sided reddish crystals embedded in a flaky or banded metamorphic matrix. Commonly found in metamorphic belts such as the Appalachians or the Alps.
More like this
