sedimentary

Weathered dark shale or slate-like rock

Fine-grained argillaceous rock; exact identification requires examination of a fresh surface

AI-generated identification · may be incorrect

Dark gray-brown, dull and fine-grained, with irregular splitting; likely dominated by clay minerals and quartz. Hardness and cleavage cannot be reliably determined from the image.

Identified October 12, 2026More sedimentary →

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At a glance

Common name: Weathered dark shale or slate-like rock
Scientific name: Fine-grained argillaceous rock; exact identification requires examination of a fresh surface
Category: sedimentary
Identified: October 12, 2026
Method: Standard

AI Estimated Value

About $0–$5 for ordinary loose pieces; higher value would require a distinctive locality, specimen quality, or confirmed identification.

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

Dark gray-brown, dull and fine-grained, with irregular splitting; likely dominated by clay minerals and quartz. Hardness and cleavage cannot be reliably determined from the image.

Formation & geological history

Likely formed from compacted mud or silt in a sedimentary basin, then exposed to weathering; its age and any metamorphic history cannot be established visually.

Uses & applications

Commonly used as fill or aggregate; suitable slate may be used for roofing, paving, or decorative stone. These weathered pieces appear to have little commercial value.

Geological facts

Shale splits along bedding planes; slate is metamorphosed shale and typically splits into flatter, more durable sheets.

Field identification & locations

The rough, layered texture suggests shale, but distinguishing it from slate or another dark fine-grained rock requires inspecting fresh surfaces and layering. Similar rocks occur in sedimentary and low-grade metamorphic terrains worldwide.