metamorphic

Fine-grained, foliated rock (possibly slate or phyllite)

Undetermined; likely slate or phyllite, composed mainly of quartz, mica, and chlorite

AI-generated identification · may be incorrect

Gray to dark gray, dull to slightly silky, with visible planar foliation and irregular fractures. Slate is typically Mohs 3–4; phyllite about 2–3. The photo does not show enough detail for a confident identification.

Identified September 26, 2026More metamorphic →

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At a glance

Common name: Fine-grained, foliated rock (possibly slate or phyllite)
Scientific name: Undetermined; likely slate or phyllite, composed mainly of quartz, mica, and chlorite
Category: metamorphic
Identified: September 26, 2026
Method: Standard

AI Estimated Value

About $1–$10 for a small, common hand specimen; higher value would require a distinctive, confirmed material or provenance.

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

Likely formed when clay-rich sedimentary rock was regionally metamorphosed under low-grade heat and pressure; age and original setting cannot be determined from the image.

Uses & applications

If confirmed as slate, it may be used for roofing, paving, or decorative stone; phyllite is sometimes used as aggregate or facing stone.

Geological facts

Slate splits into flat sheets; phyllite often has a subtle silky sheen and wavy foliation. The specimen’s rough, fractured surface makes the distinction unclear.

Field identification & locations

Look for persistent, thin splitting planes for slate or a satiny sheen and gently wavy layers for phyllite. Similar rocks occur in metamorphic belts worldwide.