fossil

Fossiliferous Limestone

Sedimentary rock containing Indeterminate Fossil remains (likely Crinoid stem or Bryozoan fragment)

Hardness: 3-4 (Mohs); Color: Light gray to tan/buff; Luster: Dull, earthy; Crystal structure: Microcrystalline (calcite matrix); Cleavage: None (fractures irregularly); Specific gravity: 2.5-2.7

Hardness: 3-4 (Mohs)
Color: Light gray to tan/buff
Luster: Dull, earthy

Identified July 5, 2026More fossil →

Explore Fossiliferous Limestone in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 3-4 (Mohs); Color: Light gray to tan/buff; Luster: Dull, earthy; Crystal structure: Microcrystalline (calcite matrix); Cleavage: None (fractures irregularly); Specific gravity: 2.5-2.7

Formation & geological history

Formed in a shallow marine environment where calcium carbonate precipitated and buried organic remains. Over millions of years, pressure and chemical changes lithified the sediment into rock. Most common in Paleozoic era deposits.

Uses & applications

Primarily used for geological study, education, and as decorative garden stones. Larger deposits of limestone are used in construction, cement production, and as crushed stone for roads.

Geological facts

This specimen shows differential weathering, where the fossilized internal structure (possibly a segment of a crinoid stem or bryozoan) is slightly more resistant or differently mineralized than the surrounding matrix, causing it to stand out in relief.

Field identification & locations

Identify in the field by looking for grayish rocks with visible patterns, tubes, or shell shapes. It will fizz when exposed to a weak acid like vinegar (HCl test). Common in areas with ancient seabed exposure.

Other fossil specimens

See all

Sedimentary Outcrop (Sandstone/Shale)

Sedimentary bedrock formation (variable composition)

sedimentary

Fossiliferous Limestone

Fossiliferous Calcilutite / Biomicrite

sedimentary

Fossiliferous Limestone

Biogenic Limestone with Brachiopod/Crinoid fragments

sedimentary

Fossilized Crinoid Stem in Limestone

Crinoidea (Class) in Calcium Carbonate (CaCO3) matrix

fossil

Fossiliferous Limestone

Limestone with embedded fossil cross-section

sedimentary

Fossiliferous Limestone with Crinoid stems

Limestone (CaCO3) containing Crinoidea fossils

sedimentary