Rockhounding Map & Sites in Indiana: 68 Locations for Crystal Hunting, Gem Mining & More

Indiana produces excellent quartz geodes from Mississippian-age limestones and shales, particularly in the southern third of the state. The Hoosier National Forest and surrounding counties in the Crawford Upland sit on the same Keokuk and Warsaw Limestone formations that produce the famous Keokuk geodes across the river in Illinois and Iowa.

Top sites:

• Hoosier National Forest, Brown/Monroe counties — Creek beds and eroded hillsides expose geodes weathering out of Mississippian limestone. Surface collecting is permitted for personal use. Sedan access to trailheads; short hikes to creek exposures.
• Loogootee area, Martin County — Road cuts and creek gravels along the East Fork of the White River produce geodes ranging from 2 inches to over a foot in diameter.

Indiana geodes are typically lined with clear to milky quartz crystals. Some contain calcite, dolomite, pyrite cubes, or sphalerite. The exterior rind is rough chalcedony, often stained brown with iron oxide. Shake the geode — if you hear water sloshing, it is an enhydro specimen (water-filled). These are uncommon and worth keeping intact. Bring a shovel, pry bar, and rock hammer. A 5-gallon bucket fills fast in productive creeks.

Indiana contains two world-class fossil localities. The Falls of the Ohio in Clark County exposes one of the largest Devonian fossil reefs on Earth — a 390-million-year-old reef system visible at low water. Crawfordsville in Montgomery County is the global type locality for Mississippian crinoid fossils, preserved in extraordinary three-dimensional detail in the Edwardsville Formation.

Top sites:

• Falls of the Ohio State Park, Clark County (Clarksville) — Exposed Devonian reef flat along the Ohio River. Massive tabulate and rugose corals, brachiopods, and bryozoans visible at low water. Collecting is prohibited — observation only. Sedan access. The interpretive center has reference specimens.
• Crawfordsville, Montgomery County — Mississippian crinoid beds. The classic sites on private farmland occasionally open for organized digs. Contact the county tourism office or local rock clubs for access. Sedan access.

Beyond these two sites, Ordovician and Silurian fossils are common in limestone road cuts and quarries statewide. Brachiopods, horn corals, and trilobite fragments appear in the Waldron Shale (Shelby County) and the Laurel Limestone. Bring a flat chisel, small hammer, and newspaper for wrapping delicate crinoid calyxes.

Indiana sits on thick Paleozoic limestone sequences, and active and abandoned quarries across the state produce calcite crystals, geodes, and mineral specimens. The Salem Limestone (Mississippian) — the famous "Indiana Limestone" used in buildings nationwide — is quarried in Lawrence and Monroe counties. These quarry walls and waste piles occasionally yield well-formed calcite crystals, druzy quartz, and celestine.

Top sites:

• Bedford, Lawrence County — The Indiana Limestone belt. Abandoned quarries near Bedford expose calcite-lined vugs and cavities in the Salem Limestone. Some quarries allow collecting with permission from the operator. Sedan access.
• Bloomington area, Monroe County — Active and abandoned quarries produce dogtooth calcite crystals, some exceeding 3 inches. Always contact the quarry owner before entering — active quarries are dangerous and trespassing is prosecuted.

Calcite in Indiana limestone is typically honey-yellow to clear dogtooth (scalenohedral) habit, growing in solution cavities. Calcite is soft (hardness 3) and cleaves easily — wrap specimens individually in newspaper. Some quarries also produce pyrite, marcasite, and small fluorite cubes. Bring a chisel, crack hammer, safety glasses, and a hard hat if entering any quarry area.