sedimentary

Fossiliferous Sedimentary Rock (Coquina/Limestone)

Fossiliferous Calcarenite / Bioclastic Limestone

AI-generated identification · may be incorrect

Hardness: 3-4 (Mohs); Color: Red-brown matrix with white/cream clasts; Luster: Dull to earthy; Structure: Clastic with visible shell fragments and smooth rounded grains; Specific Gravity: 2.3-2.7

Hardness: 3-4 (Mohs)
Color: Red-brown matrix with white/cream clasts
Luster: Dull to earthy

Identified May 19, 2026More sedimentary →

Explore Fossiliferous Sedimentary Rock (Coquina/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: 3-4 (Mohs); Color: Red-brown matrix with white/cream clasts; Luster: Dull to earthy; Structure: Clastic with visible shell fragments and smooth rounded grains; Specific Gravity: 2.3-2.7

Formation & geological history

Formed in marine or fluvial environments through the accumulation and lithification of calcium carbonate shell fragments and clastic sediments. The red hue suggests iron oxide presence. Likely from the Paleozoic or Mesozoic eras depending on local stratigraphy.

Uses & applications

Primarily used for geological study, education, and as decorative stone or landscaping. Historically used as building material in some regions.

Geological facts

The white inclusion patterns resemble Crinoid stems or small bivalve fragments embedded in a ferruginous sandstone or siltstone matrix. It is a snapshot of an ancient marine or riverbed environment.

Field identification & locations

Identify by looking for visible skeletal remains or shell impressions embedded in a matrix. It is commonly found in areas with exposed sedimentary basins. Acid testing with vinegar will often cause a fizzing reaction due to calcite content.