metamorphic

Banded metamorphic rock, likely gneiss or foliated amphibolite

Quartz–feldspar–mica gneiss or amphibolite; exact identification requires testing

AI-generated identification · may be incorrect

Gray-green, fine- to medium-grained, strongly foliated and contorted, with a dull to slightly silky luster. Typical hardness is about 5–7 Mohs; mineral grains and specific gravity cannot be confirmed from the image.

Identified September 9, 2026More metamorphic →

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At a glance

Common name: Banded metamorphic rock, likely gneiss or foliated amphibolite
Scientific name: Quartz–feldspar–mica gneiss or amphibolite; exact identification requires testing
Category: metamorphic
Identified: September 9, 2026
Method: Standard

AI Estimated Value

About $5–$30 for a common hand specimen; roughly $30–$100 if unusually well-patterned, polished, or locality-documented.

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 preexisting igneous or sedimentary rock underwent high-pressure, high-temperature metamorphism, producing folded mineral banding. Its geological age is indeterminate from appearance alone and may range from Precambrian to younger.

Uses & applications

Used locally as decorative stone, landscaping material, and aggregate; attractive polished pieces may be sold as specimens, though this example appears chiefly collectible rather than gem-quality.

Geological facts

The wavy light-and-dark fabric records ductile deformation during metamorphism. Green coloration may indicate amphibole, chlorite, epidote, or other mafic minerals.

Field identification & locations

Look for planar foliation, alternating light and dark mineral bands, and resistance to scratching with a steel knife; a streak, acid, hardness, and thin-section test would distinguish gneiss from amphibolite or schist. Common in ancient metamorphic belts worldwide.