fossil

Polished fossiliferous limestone, possibly ammonite-bearing

Calcite-rich limestone (CaCO₃), with visible fossil or shell fragments

AI-generated identification · may be incorrect

Gray to brown, polished surface with swirling fossil-like patterns and a dull to vitreous luster; calcite hardness is Mohs 3, with good rhombohedral cleavage and specific gravity about 2.7. The specimen appears cut and polished, making texture-based identification less certain.

Identified August 28, 2026More fossil →

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At a glance

Common name: Polished fossiliferous limestone, possibly ammonite-bearing
Scientific name: Calcite-rich limestone (CaCO₃), with visible fossil or shell fragments
Category: fossil
Identified: August 28, 2026
Method: Standard

AI Estimated Value

About $5–$30 for a small polished specimen; $30–$100+ if the fossil pattern is distinctive, well preserved, or locally documented.

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 shell material, commonly during the Paleozoic–Mesozoic eras; later lithification and polishing exposed the fossil structures. The exact age and locality cannot be determined from the image alone.

Uses & applications

Used as an ornamental stone, cabochon, paperweight, or collector specimen; fossiliferous limestone is also used for building stone and cement manufacture.

Geological facts

Acid testing with a drop of dilute hydrochloric acid or vinegar should produce effervescence if calcite-rich. Dark swirling areas may represent fossil shells, micritic limestone, or mineral-filled cavities rather than a single identifiable fossil.

Field identification & locations

Common sources include Morocco, Madagascar, the United Kingdom, and many marine sedimentary basins. Confirm with a hand lens, acid test on an inconspicuous spot, and examination of shell symmetry or chamber walls.