sedimentary
Fossiliferous Limestone
Calcium Carbonate (CaCO3) with Biogenic Fossils
Hardness: 3 on Mohs scale (calcite matrix). Color: Gray, tan, light brown with white shell fragments. Luster: Dull to earthy matrix with vitreous fossil inclusions. Structure: Clastic/Biogenic, massive with visible fossil voids and shells.
- Hardness
- 3 on Mohs scale (calcite matrix)
- Color
- Gray, tan, light brown with white shell fragments
- Luster
- Dull to earthy matrix with vitreous fossil inclusions
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Physical properties
Hardness: 3 on Mohs scale (calcite matrix). Color: Gray, tan, light brown with white shell fragments. Luster: Dull to earthy matrix with vitreous fossil inclusions. Structure: Clastic/Biogenic, massive with visible fossil voids and shells.
Formation & geological history
Formed in shallow, warm marine environments where biological debris (such as shells, crinoids, or corals) accumulated on the seafloor and were compacted and cemented by calcite precipitation over millions of years.
Uses & applications
Used widely as crushed stone for road construction, lime production, cement manufacturing, soil conditioner in agriculture, and building stone. Specimen collecting is common.
Geological facts
Fossiliferous limestone acts as a historical record of ancient marine life. Dissolves easily in weak acids (like vinegar), producing carbon dioxide gas bubbles.
Field identification & locations
Identified in the field by its soft calcite matrix (scratchable with a copper penny or steel nail), effervescence with diluted hydrochloric acid, and embedded shell fragments or fossils. Commonly found in sedimentary basins worldwide.
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