Fredericktown: Aragonite & Azurite Rockhounding in Madison County, Missouri

Plan your visit

Generally open to casual rockhounding

County

Madison County

State

Missouri

Nearest road

County Road 274

Coordinates

37.61538, -90.28467

Coordinates are approximate. Confirm the exact ground in the RockHoundR app, where land overlays show which agency manages the area.

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.

Best time to visit Fredericktown

Comfortable months (45 to 90°F highs)

Best months: February to December. Typical highs run 88°F in midsummer and 41°F in midwinter, with winter lows near 20°F.

Climate normals: NOAA 1991-2020 monthlies, FREDERICKTOWN station (4 mi away).

Geology at Fredericktown

This spot sits on Elvins Group - (including Derby-Doerun Dolomite, Davis Formation), Bonneterre Dolomite, mapped as dolostone, shale, and siltstone that formed roughly 495 to 485 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

Elvins Group - (including Derby-Doerun Dolomite, Davis Formation), Bonneterre Dolomite

Age

495–485 Ma (Furongian)

Rock types

dolostone, shale, and siltstone

Elevation

830 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.

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.

• Missouri Geological Survey
• Mark Twain National Forest
• Missouri State Parks rules
• Community submissions reviewed against published agency rules