Brachiopod Fossil in Limestone

Physical Properties

Hardness: 3 (limestone matrix); Color: Tan/Grey; Luster: Dull/Earthy; Structure: Symmetrical bivalved shell with ribbing; Cleavage: None; Specific Gravity: Approx 2.7

Formation & Geological History

Formed in shallow marine environments during the Paleozoic or Mesozoic eras (approx. 50-500 million years ago) through the mineralization of marine shells within lime mud.

Uses & Applications

Scientific study, educational tools, fossil collecting, and occasionally used in limestone production for construction.

Geological Facts

Brachiopods are not clams; while they look like bivalve mollusks, they are their own distinct phylum. They survived the 'Great Dying' mass extinction, though their diversity was drastically reduced.

Field Identification & Locations

Identify by radial ribbing and bilateral symmetry across the surface of the shell valve. Commonly found in limestone road cuts, creek beds, and quarries globally.

Identified on: 5/2/2026

Mode: Standard