sedimentary

Fossiliferous Limestone

Limestone (CaCO3 - Calcium Carbonate)

AI-generated identification · may be incorrect

Hardness: 3 (Mohs scale); Color: Tan, beige, or gray; Luster: Dull/Earthy; Structure: Clastic or Biogenic; Cleavage: None; Specific Gravity: 2.3-2.7

Hardness: 3 (Mohs scale)
Color: Tan, beige, or gray
Luster: Dull/Earthy

Identified May 21, 2026More sedimentary →

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Physical properties

Hardness: 3 (Mohs scale); Color: Tan, beige, or gray; Luster: Dull/Earthy; Structure: Clastic or Biogenic; Cleavage: None; Specific Gravity: 2.3-2.7

Formation & geological history

Formed in shallow, calm, warm marine waters by the accumulation of shell, coral, algal, and fecal debris. This specimen appears to be a water-worn river pebble or beach stone consisting of lithified marine sediments.

Uses & applications

Used in construction, lime production, cement, and as a soil conditioner. Fossil-rich specimens are popular with collectors and used in decorative stone.

Geological facts

Limestone makes up about 10% of the total volume of all sedimentary rocks on Earth. This specific specimen shows pits and molds where organic matter or softer minerals have weathered away.

Field identification & locations

Identify by its reaction (fizzing) with diluted hydrochloric acid. Look for visible shell fragments or small circular patterns (crinoids/ooids). Commonly found in ancient inland sea beds.