sedimentary

Fossiliferous Limestone

Biogenic Limestone (Calcium Carbonate, CaCO3)

AI-generated identification · may be incorrect

Hardness: 3 (Mohs scale); Color: gray to light tan; Luster: dull/earthy; Texture: fine-grained matrix containing visible fossil fragments; Cleavage: none (conchoidal fracture).

Hardness: 3 (Mohs scale)
Color: gray to light tan
Luster: dull/earthy

Identified June 12, 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

Hardness: 3 (Mohs scale); Color: gray to light tan; Luster: dull/earthy; Texture: fine-grained matrix containing visible fossil fragments; Cleavage: none (conchoidal fracture).

Formation & geological history

Formed in shallow, calm, warm marine waters from the accumulation of shell, coral, algal, and fecal debris. These rocks often date from many geological periods, frequently Paleozoic or Mesozoic eras.

Uses & applications

Used in the production of cement, as a building stone, in road base construction, and as a soil conditioner in agriculture. Small fossiliferous pieces are popular in educational collections.

Geological facts

Limestone makes up about 10% of the total volume of all sedimentary rocks. It is the primary source of lime for the steel industry and chemical applications.

Field identification & locations

Identified by its reaction (fizzing) when exposed to dilute hydrochloric acid and the presence of visible biological remains. Commonly found in areas that were formerly ancient seabeds.