Rockhounding in Linn County, Iowa

1 mapped rockhounding spot in Linn County. Most commonly produces calcified coral, silicified coral.

Linn County rockhounding photos

Representative spot and material photos from this county, shown where verified public image records are available.

1 photo

The Cedar River and a railroad bridge at Cedar Rapids, Linn County, Iowa — Cedar RapidsLinn County, Iowa

Minerals reported in Linn County

Calcified Coral1
Silicified Coral1

Standout in Linn County

Hand-picked spot in Linn County, chosen for unusual mineralogy or documented public access. Each card opens the full coordinates and access notes.

Top pick
Cedar Rapids
Public
Linn County
The Cedar River gravels around Cedar Rapids carry silicified Devonian coral weathered out of the Cedar Valley Group limestones that underlie eastern Iowa. Colonial corals such as Hexagonaria and Favosites survive as hard, silica-replaced heads that take a good polish. The same gravels yield glacial agates and jaspers, making this a productive mixed-bag stretch.
Silicified Coral, Calcified Coral

Spots in Linn County

Spot	Minerals	Coordinates	Access
Cedar Rapids29th Ave Dr SW	Silicified Coral Calcified Coral	41.9419, -91.6512	Public

Neighboring counties in Iowa

Adjacent rockhounding counties, ranked by how close their centroids sit to Linn County. A natural extension if Linn County is already on your trip plan.

Across the state line from Linn County

Rockhounding counties in neighboring states within driving range. Geology rarely respects state borders — these are often the closest mapped spots you can reach without going deeper into Iowa.

Linn County FAQ

Where can I rockhound in Linn County, Iowa?+

RockHoundR tracks 1 rockhounding spot in Linn County. Each entry below has coordinates, mineral notes, and access type. Always confirm local rules before collecting.

What rocks and minerals are common in Linn County?+

Spots in Linn County most often produce Calcified Coral, Silicified Coral. Individual spots can vary widely.

Are these Linn County rockhounding spots on public land?+

Most spots in this list are tagged public, but access can change with seasons, claims, and local closures. Always verify before driving out — links in the app open the right BLM, USFS, or county pages.

Plan a Linn County rockhounding trip

Open RockHoundR to see these spots on the map alongside land overlays, weather, geology, and your saved finds.