Best spot

Cave-In Rock: Barite & Calcite Rockhounding in Hardin County, Illinois

Updated July 2026

Cave-In Rock sits at the heart of the Illinois-Kentucky Fluorspar District, the largest fluorite-producing region in United States history and the reason fluorite is the Illinois state mineral. Its Mississippi Valley-type deposits yielded cubic fluorite in purple, amber, yellow, and blue, alongside galena, sphalerite, barite, calcite, and the rare barium minerals witherite and benstonite. Mining ended in the 1990s, leaving dumps that still produce cabinet-grade crystals. Reported finds include barite, calcite, cerussite, chalcopyrite, fluorite, and more. Below: coordinates, access notes, nearby spots, and trip-planning links.

Cave-In Rock photos

Public image records connected to this spot or its reported material.

1 photo

The cave at Cave-In-Rock State Park in the Ohio River bluff, Hardin County, Illinois, in the heart of the Illinois-Kentucky Fluorspar District

Quick details

Access: Public area
County: Hardin County
State: Illinois
Nearest road: Hastie Mine Road
Postcode: 62919
Coordinates: 37.50321, -88.20518

Geology at Cave-In Rock

This spot sits on Ste. Genevieve Limestone, mapped as limestone that formed roughly 345 to 330 million years ago. Carbonate rock like this dissolves and weathers readily, so fresh road cuts, quarries, and creek exposures are typically the most productive ground.

Mapped unit: Ste. Genevieve Limestone
Age: 345–330 Ma (Mississippian)
Rock types: limestone
Elevation: 460 ft

Geologic mapping via Macrostrat and the underlying state geological survey maps (CC BY 4.0). Bedrock at the surface can vary within a mapped unit.

Best time to visit Cave-In Rock

Best months: February to December. Typical highs run 86°F in midsummer and 41°F in midwinter, with winter lows near 22°F.

Climate normals: NOAA 1991-2020 monthlies, ELIZABETHTOWN station (7 mi away).

Land & collecting status

Generally open to casual rockhounding

Most public-tagged spots sit on BLM, U.S. Forest Service, or other federal land where reasonable hand collecting of common rocks and minerals is allowed. Confirm posted rules and active mining claims before you dig.

Public-land rules vary by agency, season, and field office. The RockHoundR app pulls live BLM, USFS, NPS, and tribal overlays so you can see exactly which agency manages the ground at this spot.

Sources & verification

Spot details combine the public RockHoundR location dataset, normalized mineral labels, agency land-status checks in the app, and community submissions. Coordinates are approximate until verified in the field.

Sources: RockHoundR public spot dataset, app land overlays, and local agency review before each trip.

Found at Cave-In Rock

Each chip opens all spots that produce that material; the encyclopedia link opens the full ID and field guide.

Nearby rockhounding spots

Other rockhounding spots within driving distance of Cave-In Rock.

Across the state line from Cave-In Rock

Cave-In Rock is close enough to the Illinois border that the next-closest rockhounding spots are in a neighboring state. Worth knowing if you are already on the road.

Cave-In Rock FAQ

Where is Cave-In Rock?+

Cave-In Rock is in Hardin County, Illinois, at 37.50321, -88.20518. Nearest road: Hastie Mine Road.

What rocks and minerals can you find at Cave-In Rock?+

Cave-In Rock is reported to produce Barite, Calcite, Cerussite, Chalcopyrite, Fluorite, Galena, Pyrite, Smithsonite, Witherite.

Is collecting allowed at Cave-In Rock?+

Generally open to casual rockhounding. Most public-tagged spots sit on BLM, U.S. Forest Service, or other federal land where reasonable hand collecting of common rocks and minerals is allowed. Confirm posted rules and active mining claims before you dig. Always confirm current rules with the managing agency before a trip.

What tools should I bring to Cave-In Rock?+

A rock hammer, gloves, and safety glasses are enough for oxidized copper ground. Look for green and blue staining on weathered rock and in old dump piles.

When is the best time to visit Cave-In Rock?+

The most comfortable months at Cave-In Rock are February to December.

How do I get to Cave-In Rock?+

Open the directions link to navigate to 37.50321, -88.20518 in Google Maps. The nearest road is Hastie Mine Road.

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