sedimentary

Fossiliferous Limestone

Calcium Carbonate (CaCO3)

AI-generated identification · may be incorrect

Hardness: 3 (Mohs scale); Color: Gray to off-white; Luster: Dull to earthy; Crystal structure: Trigonal/Microcrystalline; Cleavage: Perfect rhombohedral in calcite crystals, though often obscured in rock form.

Hardness: 3 (Mohs scale)
Color: Gray to off-white
Luster: Dull to earthy

Identified June 1, 2026More sedimentary →

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

Formation & geological history

Formed in marine environments from the accumulation of organic debris such as shell, coral, and algal material, cemented by calcium carbonate over millions of years.

Uses & applications

Used primarily in construction for building stone, road base, and as an ingredient in cement. Small fossil-rich specimens are popular for educational purposes and entry-level collecting.

Geological facts

This specimen contains visible fossil fragments, likely crinoids or shell pieces, common in Paleozoic limestone layers. Limestones form more than 10% of the total volume of all sedimentary rocks.

Field identification & locations

Identified by its gray color and the presence of organic prehistoric structures. It will react and fizz (effervesce) if touched with a weak acid like vinegar due to the presence of calcite.