fossil

Fossil coral fragment

Likely calcitic colonial coral, possibly fossilized scleractinian coral

AI-generated identification · may be incorrect

Cream-white, porous, irregular branching texture with small corallite cavities; typically Mohs 3–4, vitreous to dull luster, and composed mainly of calcite (CaCO₃). Cleavage is rhombohedral, but details are indistinct in this small specimen.

Identified August 10, 2026More fossil →

Explore Fossil coral fragment in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

An ancient coral colony was buried in marine sediment and mineralized, commonly during the Paleozoic or Mesozoic; exact age cannot be determined from the image. Diagenesis commonly replaces aragonite coral skeleton with calcite.

Uses & applications

Used as a teaching specimen, fossil collectible, and occasionally in decorative displays; it has little industrial or jewelry value at this size.

Geological facts

The repeated cup- or honeycomb-like structures are biological corallites, distinguishing fossil coral from ordinary limestone or modern coral debris.

Field identification & locations

Identify by its organized radial or honeycomb pores, unlike random vesicles in volcanic rock; common sources include Florida, Michigan, Morocco, Madagascar, and many ancient shallow-marine limestone regions.