sedimentary

Weathered sandstone or fine-grained graywacke

Clastic sedimentary rock; chiefly quartz (SiO₂), feldspar, and lithic fragments bound by silica, calcite, or iron-oxide cement

AI-generated identification · may be incorrect

Hardness about 6–7 for quartz grains; gray to brown, dull earthy luster, fine granular texture, and no visible cleavage. The rough, weathered surface suggests cemented sand-sized particles rather than a crystalline igneous rock.

Identified September 20, 2026More sedimentary →

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At a glance

Common name: Weathered sandstone or fine-grained graywacke
Scientific name: Clastic sedimentary rock; chiefly quartz (SiO₂), feldspar, and lithic fragments bound by silica, calcite, or iron-oxide cement
Category: sedimentary
Identified: September 20, 2026
Method: Standard

AI Estimated Value

Typically $1–$20 for an ordinary hand specimen; $20–$100+ for unusual fossiliferous, vividly colored, or architecturally attractive pieces.

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 sand accumulated, was compacted, and cemented in a river, delta, beach, or marine basin; age cannot be determined from the image and may range from Precambrian to recent geologic periods.

Uses & applications

Commonly used as building stone, paving, aggregate, and decorative facing; attractive varieties are used for landscaping and architectural slabs. This rough fragment has little gem or collector value.

Geological facts

Sandstone commonly preserves ripple marks, cross-bedding, mud cracks, and fossils. Graywacke is a darker, poorly sorted sandstone often deposited by underwater turbidity currents.

Field identification & locations

Look for individual sand grains, bedding, and gritty texture; it generally scratches glass if quartz-rich and may react weakly with dilute acid if calcite-cemented. Common worldwide in sedimentary basins and mountain belts.