sedimentary

Fossiliferous Limestone

Limestone with fossil inclusions (CaCO3)

AI-generated identification · may be incorrect

Hardness: 3-4 on Mohs scale; Color: Gray, tan, or buff with visible whitish fossil fragments; Luster: Dull/Earthy; Structure: Clastic or Biogenic; Cleavage: None (conchoidal to irregular fracture).

Hardness: 3-4 on Mohs scale
Color: Gray, tan, or buff with visible whitish fossil fragments
Luster: Dull/Earthy

Identified May 9, 2026More sedimentary →

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Physical properties

Hardness: 3-4 on Mohs scale; Color: Gray, tan, or buff with visible whitish fossil fragments; Luster: Dull/Earthy; Structure: Clastic or Biogenic; Cleavage: None (conchoidal to irregular fracture).

Formation & geological history

Formed in shallow, warm marine environments through the accumulation of shell, coral, algal, and fecal debris over millions of years. This specimen shows significant weathering and biogenic debris typical of Paleozoic or Mesozoic age deposits.

Uses & applications

Used primarily in construction (crushed stone, cement), agriculture (lime), and as a collector's specimen for paleontological interest.

Geological facts

Limestone makes up about 10% of the total volume of all sedimentary rocks. It often contains perfectly preserved organisms that lived millions of years ago. This particular piece appears to be a fragment of a larger bed containing brachiopods or crinoid stems.

Field identification & locations

Identify in the field by its reaction (fizzing) when exposed to dilute hydrochloric acid and the presence of visible fossil remains. It is found globally in regions that were once ancient sea beds.