metamorphic
Garnet Schist
Almandine-mica schist
Hardness: 6.5-7.5 (garnets), Color: Reddish-brown crystals in grey/brown matrix, Luster: Vitreous to sub-vitreous, Crystal structure: Isometric (garnets), Cleavage: None, Specific gravity: 3.5-4.3
- Hardness
- 6
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Physical properties
Hardness: 6.5-7.5 (garnets), Color: Reddish-brown crystals in grey/brown matrix, Luster: Vitreous to sub-vitreous, Crystal structure: Isometric (garnets), Cleavage: None, Specific gravity: 3.5-4.3
Formation & geological history
Formed under regional metamorphism of clay-rich sedimentary rocks (pelites) at medium to high temperatures and pressures, typically during orogenic (mountain-building) events.
Uses & applications
Industrial abrasives, waterjet cutting, sandblasting, and occasionally as lower-grade gemstones or collector specimens.
Geological facts
Garnets are index minerals used by geologists to determine the degree of metamorphism a rock has undergone. This specimen displays porphyroblastic texture where large crystals grew within a finer matrix.
Field identification & locations
Identify by the presence of hard, reddish dodecahedral or trapezohedral crystals embedded in a foliated, micaceous, or earthy matrix. Common in metamorphic belts like the Appalachians or Himalayas.
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