sedimentary

Limestone (Fossiliferous)

Calcium Carbonate (CaCO3)

AI-generated identification · may be incorrect

Hardness: 3 on Mohs scale; Color: Gray to tan; Luster: Dull/Earthy; Crystal Structure: Trigonal (microcrystalline); Cleavage: None/Conchoidal; Specific Gravity: 2.3–2.7

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

Identified April 9, 2026More sedimentary →

Explore Limestone (Fossiliferous) 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 on Mohs scale; Color: Gray to tan; Luster: Dull/Earthy; Crystal Structure: Trigonal (microcrystalline); Cleavage: None/Conchoidal; Specific Gravity: 2.3–2.7

Formation & geological history

Formed in marine environments from the accumulation of shell, coral, algal, and fecal debris. It can be millions of years old, often dating from the Paleozoic or Mesozoic eras.

Uses & applications

Used primarily in construction (crushed stone), cement manufacturing, soil conditioning in agriculture, and as a source of lime.

Geological facts

Limestone makes up about 10% of the total volume of all sedimentary rocks. When it contains visible fossils, as seen in the texture here, it is referred to as fossiliferous limestone.

Field identification & locations

Identify in the field by its reaction (fizzing) to a drop of dilute hydrochloric acid. Commonly found in quarries and surface outcrops in areas once covered by ancient seas.