metamorphic

Likely garnet-bearing metamorphic rock

Garnet amphibolite or garnet-bearing schist; probable almandine garnet (Fe₃Al₂Si₃O₁₂) with amphibole, mica, quartz, and feldspar

AI-generated identification · may be incorrect

Dark gray-black, coarse and strongly crystalline, with reddish-purple garnet-like patches and a vitreous to submetallic luster. Garnet hardness is about 6.5–7.5 Mohs; the matrix is likely softer, with no obvious cleavage in garnet but possible cleavage or foliation in amphibole/mica.

Identified September 2, 2026More metamorphic →

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At a glance

Common name: Likely garnet-bearing metamorphic rock
Scientific name: Garnet amphibolite or garnet-bearing schist; probable almandine garnet (Fe₃Al₂Si₃O₁₂) with amphibole, mica, quartz, and feldspar
Category: metamorphic
Identified: September 2, 2026
Method: Standard

AI Estimated Value

Approximately $5–$30 for an ordinary hand specimen; $50–$150 if garnet crystals are unusually large, sharp, and attractive.

Not an official valuation

AI estimate for general interest only — not an appraisal. Actual value depends on condition, provenance, and market demand. Verify with a professional before buying, selling, or insuring.

This identification was generated by AI and may contain errors. Verify important details before relying on them — and never use an AI result to judge whether a specimen is safe to handle. Read the full disclaimer

Physical properties

Formation & geological history

Formed when a mafic or clay-rich protolith was subjected to elevated temperature and pressure during regional metamorphism, typically during Precambrian to Paleozoic mountain-building. Exact age and identification require thin-section or chemical testing.

Uses & applications

Primarily a collectible specimen; garnet may be used as an abrasive or gemstone, while amphibolite can serve as crushed stone or dimension stone. This irregular piece has limited commercial value.

Geological facts

The reddish grains may be garnet, but the image alone cannot exclude iron oxides, epidote, or other minerals. Garnet-bearing metamorphic rocks commonly record deep burial and tectonic uplift.

Field identification & locations

Look for hard, rounded red crystals embedded in a dark foliated or granular matrix; a streak, hardness, magnetism, and acid test can help. Common settings include metamorphic belts worldwide, especially Scandinavia, India, Madagascar, and the Appalachians.