fossil

Fossiliferous limestone

Bioclastic carbonate rock, primarily calcite (CaCO₃), containing fossil shell fragments and molds

AI-generated identification · may be incorrect

Typically cream to tan, porous, and dull to slightly earthy; calcite has Mohs hardness 3, rhombohedral cleavage, and reacts vigorously with dilute hydrochloric acid. The visible textures are likely bryozoans, mollusks, or other marine invertebrate remains.

Identified September 4, 2026More fossil →

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Physical properties

Formation & geological history

Forms when marine organisms accumulate on the seafloor, become buried, and are cemented or recrystallized into limestone. The exact age cannot be determined from the photograph; comparable specimens range from Paleozoic to Cenozoic.

Uses & applications

Used as aggregate, cement and lime feedstock, building stone, and decorative material; attractive fossil pieces are sold for education and collecting.

Geological facts

Fossils may appear as whole shells, cross-sections, casts, or dissolution cavities. Weathering preferentially exposes the fossil-rich texture and produces its irregular surface.

Field identification & locations

Identify it by abundant fossil structures, low hardness, light color, and fizzing with dilute acid; common in former shallow-marine limestone deposits worldwide. Avoid acid testing if preservation is important.