sedimentary

Fossiliferous Limestone

Calcium Carbonate (CaCO3) with fossil inclusions

AI-generated identification · may be incorrect

Hardness: 3 on Mohs scale; Color: Gray to tan; Luster: Dull or earthy; Crystal structure: Trigonal (calcite matrix); Cleavage: Perfect rhombohedral in calcite crystals but often massed; Specific gravity: 2.7.

Hardness: 3 on Mohs scale
Color: Gray to tan
Luster: Dull or earthy

Identified June 8, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed in marine environments through the accumulation of organic debris such as shell, coral, and algal fragments over millions of years, typically during the Paleozoic or Mesozoic eras.

Uses & applications

Used in construction, as a building stone (dimension stone), in the production of lime and cement, as an abrasive, and small fossil specimens are popular for educational purposes and hobbyist collecting.

Geological facts

This specimen contains visible fossilized remains, likely brachiopods or crinoids. Limestone makes up about 10 percent of the total volume of all sedimentary rocks on Earth.

Field identification & locations

Identify in the field by looking for visible shell fragments and testing with a drop of cold dilute hydrochloric acid (it will fizz). Commonly found in areas that were once prehistoric seafloors.