sedimentary

Possible sandstone cobble or weathered basalt

Indeterminate lithic specimen; likely quartz-rich sandstone, possibly weathered basalt

AI-generated identification · may be incorrect

Gray-brown, fine-grained, dull earthy luster, rounded and elongated from abrasion; apparent hardness roughly 5–7, with no visible cleavage or crystals. Numerous small pits and a porous-looking surface are consistent with weathered sandstone, though the image cannot exclude volcanic rock.

Identified August 30, 2026More sedimentary →

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At a glance

Common name: Possible sandstone cobble or weathered basalt
Scientific name: Indeterminate lithic specimen; likely quartz-rich sandstone, possibly weathered basalt
Category: sedimentary
Identified: August 30, 2026
Method: Standard

AI Estimated Value

About $0–$15 as an ordinary cobble; potentially $20–$100+ only with documented archaeological, fossil, or unusual locality significance.

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 a naturally water-worn or glacially transported cobble, formed over geologic time and later rounded by erosion; exact age and formation environment require locality and testing.

Uses & applications

Usually a common geological or archaeological-looking hand specimen with little commercial value; sandstone may be used as building stone, while basalt is used for aggregate and construction.

Geological facts

The elongated shape and uniformly rounded ends strongly indicate transport abrasion or deliberate shaping. A streak, acid, hardness, and thin-section test would distinguish sandstone from basalt.

Field identification & locations

Check for visible quartz grains and gritty texture (sandstone) versus a dense, dark, interlocking texture (basalt); dilute hydrochloric acid tests for carbonate cement. Common in river gravels, beaches, glacial deposits, and weathered outcrops.