Coral
Hexagonaria
Petoskey stone coral
Hexagonaria percarinata is the Devonian colonial rugose coral that becomes the Petoskey stone, Michigan's state stone, when tumbled and polished from the beaches of Lake Michigan; the polished hexagonal corallites show a dark 'eye'. Michigan limits beach collecting to 25 lb per person per year on state land. Unpolished Hexagonaria from the Silica and Traverse formations are also collected.
| Phylum | Cnidaria |
|---|---|
| Class | Anthozoa |
| Order | Stauriida |
| Family | Disphyllidae |
| Group | Coral |
| Rank (PBDB) | genus· Paleobiology Database |
| Author | Gürich 1896· Paleobiology Database |
| Classification (PBDB) | Cnidaria › Anthozoa › Stauriida › Disphyllidae· Paleobiology Database |
| Range (PBDB) | 443–359 Ma· Paleobiology Database |
| PBDB occurrences | 215· Paleobiology Database |
Elsewhere
- GBIF: 3250449
- PBDB: 5501
- Wikidata: Q16983143
- PBDB taxon page
- Wikipedia: Hexagonaria
- PBDB search: Hexagonaria
Cite this article
Stratum Study. "Hexagonaria" (Taxon). Stratum Study pack 2026.09, as of 2026-09-19. https://stratum.black/study/taxa/hexagonaria. Accessed 2026-09-20.
@misc{stratum-hexagonaria,
title = {Hexagonaria},
author = {{Stratum Study}},
howpublished = {\url{https://stratum.black/study/taxa/hexagonaria}},
year = {2026},
note = {Taxon article, Stratum Study pack 2026.09, as of 2026-09-19; sources: stratum, pbdb, wikidata, commons. Accessed 2026-09-20.}
} Citations carry the pack version and the article's as-of date so they resolve to the same text later. The facts themselves belong to the sources listed below; cite those for the science.