Favosites is a genus of extinct tabulate coral characterized by tightly packed polygonal corallites that resemble a honeycomb structure. Collectors typically find these fossils in Paleozoic limestone deposits, often silicified, making them excellent candidates for lapidary work and polishing.

Hardness

3-4

Mohs

Luster

Dull

Transparency

Opaque

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Favosites

Also: Honeycomb Coral

Hardness: 3-4
Luster: Dull
Transparency: Opaque

Is this favosites?

4-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try to scratch favosites with a known reference. Favosites sits at Mohs 3-4, softer than the next harder reference, harder than the previous one.
2
Name the organism
Decide what left the fossil before worrying about the rock. Organism: Tabulate coral (genus Favosites). Age: Late Ordovician to Late Permian.
3
Read the luster
Hold the specimen under a strong light. Luster: dull.
4
Match the color range
Compare against the expected color range: gray, tan, brown, white, black.

Often confused with

Favosites vs. its common look-alikes, and how to tell them apart in the field.

Often found alongside favosites

Minerals reported to co-occur with favosites. Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Mohs hardness: 3-4
Density: 2.6-2.7 g/cm³
Colors: Gray Tan Brown White Black
Luster: Dull
Transparency: Opaque
Rarity: Common
Uses: Collector, Lapidary, Decorative
Host rock: sedimentary limestone
Organism: Tabulate coral (genus Favosites)
Age: Late Ordovician to Late Permian

Where rockhounds find favosites

3 mapped spots

Classic worldwide localities

Michigan, USA
Ontario, Canada
Gotland, Sweden
Eifel, Germany

Field-hunting tip

Where it forms: sedimentary limestone. If you start seeing calcite, dolomite, quartz in float, you are in the right ground. In the U.S., the densest reported localities are in Michigan, New York, Wisconsin. Start trip planning there.

Browse 3 U.S. spots for favosites →

Common questions

How do you identify favosites?+

Mohs hardness is 3-4. Organism: Tabulate coral (genus Favosites). Luster: dull. Common colors include gray, tan, brown, white.

Where is favosites found?+

Notable localities include Michigan, USA; Ontario, Canada; Gotland, Sweden; Eifel, Germany.

Can I find favosites in the United States?+

RockHoundR maps 3 favosites rockhounding spots across 3 U.S. states. The top states are Michigan, New York, Wisconsin.

What rocks look like favosites?+

Favosites is most often confused with Chain Coral. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with favosites?+

Favosites commonly co-occurs with Calcite, Dolomite, Quartz. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does favosites form in?+

Where it forms: sedimentary limestone. Working float back to the host body is the standard way to chase a fresh occurrence.

What is favosites used for?+

Favosites is used in collector, lapidary, decorative.

Find favosites on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.