fossil

Polished fossiliferous limestone (ammonite-rich slab)

Fossiliferous micrite/wackestone, likely containing goniatites or ammonites; chiefly calcite, CaCO₃

AI-generated identification · may be incorrect

Hardness about 3 Mohs; gray, cream, and blue-gray bands with silky to dull polished luster. The repeated curved, chamber-like forms are fossil cross-sections embedded in fine-grained limestone; calcite may effervesce in dilute hydrochloric acid.

Identified August 26, 2026More fossil →

Explore Polished fossiliferous limestone (ammonite-rich slab) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

At a glance

Common name: Polished fossiliferous limestone (ammonite-rich slab)
Scientific name: Fossiliferous micrite/wackestone, likely containing goniatites or ammonites; chiefly calcite, CaCO₃
Category: fossil
Identified: August 26, 2026
Method: Standard

AI Estimated Value

Approximately $30-$150 for a polished common slab; exceptional large, well-prepared fossil slabs may sell for $200-$1,000+.

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

Marine carbonate mud lithified around Paleozoic or Mesozoic cephalopod fossils, commonly during burial and compaction; the exact age and species require locality or laboratory identification.

Uses & applications

Used as a decorative polished slab, display fossil, educational specimen, and occasionally in interior accents; it is not generally suitable for heavy construction because calcite is soft and acid-sensitive.

Geological facts

The visible coiled patterns likely represent sectioned chambered cephalopods, whose septa and shell walls became mineral-filled or replaced during fossilization.

Field identification & locations

Identify by testing for calcite reaction, examining chamber walls under magnification, and checking that patterns are natural fossils rather than painted designs. Similar material is sold from Morocco, Madagascar, Europe, and North America.