Iowa State Rock: Geode

Iowa's state rock is the geode, adopted in 1967.

Symbol names and dates are taken from primary state sources linked below. Informal or proposed symbols are not listed unless adopted.

Geode specimen — Geode (not necessarily from Iowa). Photo: James St. John, CC BY 2.0, via Wikimedia Commons

State rock: Geode

Adopted:: 1967

Geode is a sedimentary rock with a Mohs hardness of about 6.5–7 and a dull to vitreous luster, usually gray, white, purple or brown.

How to identify geode →

Often confused with: Concretion, Septarian Nodule, Thunderegg

Iowa state symbols FAQ

What is the state rock of Iowa?

Iowa's state rock is the geode, adopted in 1967.

Sources

We cite primary sources (statutes, state government pages, federal regulations, and land-manager sites). Third-party listicles are not used as citations.

Iowa State Symbols — Iowa Legislature (accessed 2026-10-24).

Last verified 2026-10-24. Corrections welcome: if a statute has changed, tell us and we'll re-verify.

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