sedimentary

Favosites Fossil (Honeycomb Coral Pebble)

Favosites goldfussi / Silicified Coral Fossil

AI-generated identification · may be incorrect

Hardness: 6.5-7 (if silicified/replaced by quartz); Color: Gray, tan, or brown; Luster: Dull to waxy; Structure: Tabular, honeycomb-like pores (corallites); Specific gravity: 2.6-2.7.

Hardness: 6
Color: Gray, tan, or brown
Luster: Dull to waxy

Identified June 20, 2026More sedimentary →

Explore Favosites Fossil (Honeycomb Coral Pebble) in the encyclopedia →

Identify your own rocks.

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

App Store Google Play

Physical properties

Hardness: 6.5-7 (if silicified/replaced by quartz); Color: Gray, tan, or brown; Luster: Dull to waxy; Structure: Tabular, honeycomb-like pores (corallites); Specific gravity: 2.6-2.7.

Formation & geological history

Formed during the Silurian to Devonian periods (approx. 400 million years ago) in warm, shallow marine environments. This specimen has been smoothed into a pebble by water erosion.

Uses & applications

Collecting, educational specimens, lapidary use (cabochons), and decorative garden stones.

Geological facts

Commonly known as Honeycomb Coral because of the hexagonal pattern of the individual coral polyps. These were colonial corals that lived long before the extinction of the dinosaurs.

Field identification & locations

Identify in the field by looking for a 'honeycomb' or grid-like pattern on the surface of smooth river or beach stones. Frequently found in the Great Lakes region and limestone outcrops.