metamorphic

Weathered metamorphic rock, likely slate or phyllite

Fine-grained foliated rock, probably quartz–mica-rich phyllite (exact identification requires testing)

AI-generated identification · may be incorrect

Gray-brown, dull to slightly satiny luster, fine-grained and visibly foliated with planar layers; likely Mohs 2–4, with imperfect cleavage along foliation. Composition may include quartz, mica, chlorite, and clay-derived minerals.

Identified September 2, 2026More metamorphic →

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At a glance

Common name: Weathered metamorphic rock, likely slate or phyllite
Scientific name: Fine-grained foliated rock, probably quartz–mica-rich phyllite (exact identification requires testing)
Category: metamorphic
Identified: September 2, 2026
Method: Standard

AI Estimated Value

About $1–$10 for a common hand specimen; $10–$30 if unusually attractive, labeled, or locally significant.

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 shale or mudstone underwent low-grade regional metamorphism during mountain building; ages vary widely, commonly Paleozoic to Precambrian depending on locality.

Uses & applications

Slate is used for roofing, paving, tiles, and writing surfaces; phyllite is mainly a decorative or educational specimen and has limited commercial value.

Geological facts

The layered texture reflects alignment of microscopic mica and clay minerals under directed pressure and heat. Its surfaces may split into thin sheets, though less cleanly than true slate.

Field identification & locations

Look for consistent planar foliation, a fine texture, and a silky sheen; a streak, hardness test, and close inspection can distinguish it from weathered shale or schist. Common in metamorphic mountain belts worldwide.