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Fayville: Agate & Jasper Rockhounding in Alexander County, Illinois

Public accessBest spot3 mineralsAlexander County, IllinoisUpdated July 2026
Minerals reported
3
Elevation
330 ft
Best months
February to December

The Mississippi River gravel bars near Fayville and Thebes, at the far southern tip of Illinois, are the state's most productive agate ground, where fortification agate and jasper accumulate in the river sediment. The southern position gathers material transported the full length of the river system. The gravel also yields clear quartz, sometimes sold locally as Illinois diamonds. Reported finds include agate, jasper, diamond. Below: coordinates, access notes, nearby spots, and trip-planning links.

Plan your visit

Generally open to casual rockhounding

Nearest road
Thebes Road
Postcode
62990
Get directionsView on Google Maps

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.

Access note: Collect from exposed gravel bars reached via public river accesses. The riverbed below the ordinary high-water mark is public-trust land, but the adjacent banks are often private, so surface-collect only and stay off posted ground. Alexander County, southernmost Illinois, along the Mississippi River near the Thebes Gap.

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 Fayville

Comfortable months (45 to 90°F highs)

Best months: February to December. Typical highs run 89°F in midsummer and 43°F in midwinter, with winter lows near 26°F.

Climate normals: NOAA 1991-2020 monthlies, CAPE GIRARDEAU MUNI AP station (7 mi away).

Geology at Fayville

This spot sits on ground mapped as dolostone and limestone that formed roughly 445 to 420 million years ago. Chert and agate nodules typically form inside carbonate rock like this and weather out as tough, waxy lumps in soils and creek beds.

Age
445–420 Ma (Llandovery to Pridoli)
Rock types
dolostone and limestone
Elevation
330 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.

Today's weather

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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.

Found at Fayville

Each name 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 Fayville.

Across the state line from Fayville

Fayville 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.

  • Cape Girardeau CountyCape Girardeau County, Missouri · 17 mi awayAgate, Petrified Wood
  • Marble Hill E General AreaBollinger County, Missouri · 27 mi awayAgate, Petrified Wood
  • LaketonCarlisle County, Kentucky · 30 mi awayYellow Ocher
  • ZionMadison County, Missouri · 48 mi awayJasper
  • DexterNew Madrid County, Missouri · 49 mi awayChert, Blue Agate, Gray Agate
  • HardmoneyGraves County, Kentucky · 52 mi awayHematite

Fayville FAQ

Where is Fayville?+
Fayville is in Alexander County, Illinois, at 37.19864, -89.45220. Nearest road: Thebes Road.
What rocks and minerals can you find at Fayville?+
Fayville is reported to produce Agate, Jasper, Diamond.
Is collecting allowed at Fayville?+
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 Fayville?+
Most agate and jasper is surface float: bring a spray bottle, a pick or small shovel, and a sturdy bag. Wet stones show their banding and translucence.
When is the best time to visit Fayville?+
The most comfortable months at Fayville are February to December.
How do I get to Fayville?+
Open the directions link to navigate to 37.19864, -89.45220 in Google Maps. The nearest road is Thebes Road.

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