fossil

Weathered fossiliferous limestone

Calcitic limestone, primarily calcium carbonate (CaCO₃), possibly containing fossil fragments

AI-generated identification · may be incorrect

Usually Mohs 3, pale gray to cream, dull to earthy luster, microcrystalline calcite with irregular cavities and possible fossil impressions; reacts vigorously with dilute hydrochloric acid. The dark reddish-brown spot may be iron staining or an exposed infilled cavity.

Identified August 22, 2026More fossil →

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Physical properties

Formation & geological history

Formed as carbonate mud and skeletal debris accumulated in a shallow marine environment, later lithified and weathered; age cannot be determined from the photograph and may range from Paleozoic to Cenozoic.

Uses & applications

Used as aggregate, cement and lime feedstock, building stone, and decorative material; fossil-bearing pieces are collected for educational and display value.

Geological facts

Limestone commonly preserves marine shells, corals, and burrows. Its porous, rounded surface indicates substantial chemical weathering or abrasion.

Field identification & locations

Common in former shallow-sea deposits worldwide, including North America, Europe, and Asia. Identify with acid reaction, low hardness, and visible fossils or carbonate textures; avoid assuming the reddish feature is a fossil without close examination.