metamorphic

Garnet in Matrix

Almandine or Pyrope Garnet (X3Y2(SiO4)3) in Schist or Eclogite matrix

AI-generated identification · may be incorrect

Hardness: 6.5-7.5 (garnets); Color: deep red to reddish-brown crystals in a light tan or greyish matrix; Luster: vitreous to resinous; Crystal structure: isometric/dodecahedral

Hardness: 6
Luster: vitreous to resinous

Identified July 21, 2026More metamorphic →

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Physical properties

Hardness: 6.5-7.5 (garnets); Color: deep red to reddish-brown crystals in a light tan or greyish matrix; Luster: vitreous to resinous; Crystal structure: isometric/dodecahedral

Formation & geological history

Forms under high pressure and temperature during regional metamorphism of clay-rich sedimentary rocks (shale) or mafic igneous rocks. Most commonly found in mica schists or gneisses.

Uses & applications

Used as an abrasive (sandpaper, waterjet cutting), gemstones in jewelry, and as an index mineral for geologists to determine metamorphic history.

Geological facts

Garnets are one of the most diverse mineral groups and can be found in almost every color except blue. They have been used as gemstones since the Bronze Age.

Field identification & locations

Identify by the characteristic round 'porphyroblast' shapes (often 12-sided) embedded in a softer matrix. Common in metamorphic belts like the Appalachians, Alps, and Himalayas.