fossil

Fossilized shell-bearing limestone

Bioclastic limestone, likely molluscan/coquina limestone (calcite, CaCO₃)

AI-generated identification · may be incorrect

A sedimentary geological specimen containing abundant shell fragments and possible partially preserved shells in a pale gray, cream, and tan calcitic matrix. Calcite has Mohs hardness 3, vitreous to earthy luster, rhombohedral cleavage, and reacts vigorously with dilute hydrochloric acid; specific gravity is about 2.7.

Identified September 21, 2026More fossil →

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Physical properties

Formation & geological history

Formed when marine shells accumulated, were compacted, and cemented on an ancient shallow seafloor; the fossils may range from Paleozoic to Cenozoic age, which requires locality or stratigraphic information to determine.

Uses & applications

Used as a decorative fossil specimen, educational material, and occasionally as ornamental or building limestone; collectible value depends mainly on fossil preservation and provenance.

Geological facts

The visible shell architecture suggests marine mollusks or other shelly invertebrates. Coquina-like limestones can preserve original shell shapes while the surrounding sediment recrystallizes into calcite.

Field identification & locations

Identify it by abundant shell fragments, porous sedimentary texture, and acid effervescence; common settings include coastal marine deposits and fossiliferous limestone beds worldwide. Avoid prolonged acid testing because it damages the specimen.