sedimentary

Fossiliferous limestone

Calcitic limestone, predominantly CaCO₃ (often containing fossilized coral or shell fragments)

AI-generated identification · may be incorrect

Usually gray to buff, dull to weakly crystalline, with visible porous fossil textures; Mohs hardness 3, non-cleaved, specific gravity about 2.3–2.7. Calcite-rich surfaces fizz vigorously with dilute hydrochloric acid.

Identified August 29, 2026More sedimentary →

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Physical properties

Formation & geological history

Forms in shallow marine environments from accumulated carbonate mud, shells, and reef organisms, commonly during Paleozoic–Cenozoic time. The prominent structure appears consistent with a fossil fragment, possibly coral, embedded in the limestone.

Uses & applications

Used for cement, aggregate, lime, building stone, and architectural slabs; attractive fossil-bearing pieces are collected or used decoratively. Generally low commercial value unless fossils are exceptionally preserved or legally collectible.

Geological facts

Limestone fossils may preserve coral colonies, brachiopods, crinoids, or mollusks; recrystallization can obscure original detail. The specimen appears naturally weathered rather than polished or manufactured.

Field identification & locations

Identify by gray carbonate matrix, fossil outlines, and acid effervescence; common in ancient marine sedimentary basins worldwide, including Europe, North America, and the Middle East. Avoid acid testing on valuable specimens and check collecting restrictions.