Permanent claim record · Michigan

The Petoskey stone became Michigan's official state stone in 1965 — a fossilized rugose coral, Hexagonaria percarinata, that lived about 350 million years ago in the Devonian period.

Verified

Raw value (vault-stripped)

{"tags":["petoskey-stone","geology","state-symbols"],"text":"The Petoskey stone became Michigan's official state stone in 1965 — a fossilized rugose coral, Hexagonaria percarinata, that lived about 350 million years ago in the Devonian period.","category":"history"}

Predicate	trivia.fact
Subject	Michigan (place)
As of
Status	Verified
Source	Famous Michiganders, Pop Culture & Trivia Report — Perplexity Deep Research (2026) (trust 6.5/10)
Reference	—
Document hash	pending evidence-pack link
Provenance chain
Claim ID	3b483b2a-15ec-4100-95ea-dec27b943967