metamorphic

Rounded blue-gray stone, likely slate or fine-grained metamorphic rock

Probable slate/phyllite; composition mainly quartz, mica, and feldspar

AI-generated identification · may be incorrect

Fine-grained, dull to subtly silky luster, blue-gray with tan weathering rind, and smoothly water-worn edges. Likely Mohs hardness 5–7; weak-to-moderate foliation may be visible, but crystal structure and cleavage are obscured by the rounded surface.

Identified September 15, 2026More metamorphic →

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At a glance

Common name: Rounded blue-gray stone, likely slate or fine-grained metamorphic rock
Scientific name: Probable slate/phyllite; composition mainly quartz, mica, and feldspar
Category: metamorphic
Identified: September 15, 2026
Method: Standard

AI Estimated Value

Typically $1–$10 as an ordinary found stone; perhaps $10–$30 if unusually attractive, polished, or associated with a documented locality.

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

Probably formed by low-grade metamorphism of shale or mudstone, commonly during Paleozoic–Precambrian mountain-building; its rounded shape indicates transport by water or glacial action.

Uses & applications

Suitable as a common decorative or landscaping stone, paperweight, or craft specimen; not identifiable as gem-quality material from the image. Slate may also be used for roofing, paving, and tiles.

Geological facts

The blue-gray color can result from fine mica, chlorite, graphite, or iron-bearing minerals. A fresh broken surface would be much more diagnostic than this weathered, polished-looking exterior.

Field identification & locations

Look for planar splitting, a fine silky sheen, and thin layers to distinguish slate/phyllite from basalt or chert; common in metamorphic terrains and stream gravels. Exact identification requires a fresh surface, streak, hardness, and possibly thin-section or chemical testing.