sedimentary

Limestone with Fossil Impression

Calcium Carbonate (CaCO3)

AI-generated identification · may be incorrect

Hardness: 3 (Mohs scale); Color: Gray to tan; Luster: Dull/Earthy; Structure: Clastic or Biogenic; Cleavage: None visible in hand specimen; Specific Gravity: 2.5-2.7

Hardness: 3 (Mohs scale)
Color: Gray to tan
Luster: Dull/Earthy

Identified July 3, 2026More sedimentary →

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Physical properties

Hardness: 3 (Mohs scale); Color: Gray to tan; Luster: Dull/Earthy; Structure: Clastic or Biogenic; Cleavage: None visible in hand specimen; Specific Gravity: 2.5-2.7

Formation & geological history

Formed in marine environments from the accumulation of shell, coral, algal, and fecal debris. This specimen shows a weathered surface with a possible interior fossil mold or 'vug' caused by partial dissolution.

Uses & applications

Primarily used as a building material, in the manufacture of cement, and as a soil conditioner. This specific piece has minimal value outside of a personal collection.

Geological facts

Limestone makes up about 10% of the total volume of all sedimentary rocks on Earth. Acid rain can easily dissolve limestone, leading to the formation of caves and sinkholes.

Field identification & locations

Identify in the field by checking if it fizzes when exposed to a drop of vinegar (acetic acid). Look for it in areas that were once prehistoric seafloors.