sedimentary

Likely fossiliferous limestone or dolostone

Micritic limestone, chiefly calcite (CaCO₃), possibly dolomitized; apparent fossil or stylolitic markings

AI-generated identification · may be incorrect

Gray to cream, fine-grained, dull to weakly crystalline with irregular darker veins and possible fossil textures; calcite hardness ~3, rhombohedral cleavage, specific gravity ~2.7. A fresh surface should fizz vigorously with dilute hydrochloric acid if calcitic limestone; dolostone reacts weakly unless powdered.

Identified September 22, 2026More sedimentary →

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At a glance

Common name: Likely fossiliferous limestone or dolostone
Scientific name: Micritic limestone, chiefly calcite (CaCO₃), possibly dolomitized; apparent fossil or stylolitic markings
Category: sedimentary
Identified: September 22, 2026
Method: Standard

AI Estimated Value

About $5–$25 as an ordinary specimen; $25–$100+ if confirmed fossiliferous, unusually patterned, or professionally prepared.

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 from compacted marine carbonate mud and/or shell debris, commonly during Paleozoic–Mesozoic marine sedimentation; the exact age cannot be determined from the photograph.

Uses & applications

Used for aggregate, cement, lime, building stone, and architectural slabs; attractive fossil-bearing pieces are collected or used decoratively.

Geological facts

The dark, branching or curved patterns may be fossil fragments, stylolites, or mineral-filled fractures rather than true crystals.

Field identification & locations

Look for bedding, fossils, and acid effervescence; common in former shallow-marine basins worldwide, including the Great Lakes, Appalachian Basin, and European carbonate platforms. Identification is provisional because the specimen is partly weathered and the image is low-resolution.