
sedimentary
Polished fossiliferous limestone
Bioclastic limestone, chiefly calcite (CaCO₃)
AI-generated identification · may be incorrectGray-blue, fine-grained carbonate rock with contrasting fossil or shell fragments and weathered cavities; typically dull to waxy when polished. Calcite hardness is Mohs 3, has rhombohedral cleavage, low specific gravity (~2.7), and effervesces strongly with dilute hydrochloric acid.
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Physical properties
Gray-blue, fine-grained carbonate rock with contrasting fossil or shell fragments and weathered cavities; typically dull to waxy when polished. Calcite hardness is Mohs 3, has rhombohedral cleavage, low specific gravity (~2.7), and effervesces strongly with dilute hydrochloric acid.
Formation & geological history
Forms from accumulated marine skeletal debris and carbonate mud that lithify through compaction and cementation, commonly during Paleozoic–Cenozoic marine deposition. The visible fossils appear partly dissolved or mineral-stained after burial and weathering.
Uses & applications
Used as a decorative polished specimen, lapidary material, and occasionally ornamental stone; limestone is widely used for cement, aggregate, and building stone.
Geological facts
The irregular pale inclusions are likely fossil fragments or shell sections rather than crystals. Yellow-brown areas may be iron-oxide staining or mineral-filled cavities.
Field identification & locations
Identify by acid reaction, softness, visible fossil textures, and lack of interlocking igneous crystals; a hand lens can reveal shell structure. Common sources include marine sedimentary basins worldwide, especially Europe, North America, and North Africa.
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