Mt. Vernon Area: Diamond Rockhounding in Jefferson County, Illinois

Updated June 2026

Mt. Vernon Area is a mapped rockhounding spot in Jefferson County, Illinois. Reported finds include diamond. Below: coordinates, access notes, nearby spots, and trip-planning links.

Quick details

Access: Public area
County: Jefferson County
State: Illinois
Nearest road: IL 15
Postcode: 62808
Coordinates: 38.30730, -89.13858

Geology at Mt. Vernon Area

This spot sits on Bond Formation, mapped as shale, sandstone, and limestone that formed about 305 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: Bond Formation
Age: 305–305 Ma (Pennsylvanian)
Rock types: shale, sandstone, and limestone
Elevation: 520 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 Mt. Vernon Area

Best months: March to November. Typical highs run 87°F in midsummer and 39°F in midwinter, with winter lows near 21°F.

Climate normals: NOAA 1991-2020 monthlies, NASHVILLE 1 E station (12 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 Mt. Vernon Area

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

Diamond Encyclopedia →

Nearby rockhounding spots

Other rockhounding spots within driving distance of Mt. Vernon Area.

Across the state line from Mt. Vernon Area

Mt. Vernon Area 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.

Mt. Vernon Area FAQ

Where is Mt. Vernon Area?+

Mt. Vernon Area is in Jefferson County, Illinois, at 38.30730, -89.13858. Nearest road: IL 15.

What rocks and minerals can you find at Mt. Vernon Area?+

Mt. Vernon Area is reported to produce Diamond.

Is collecting allowed at Mt. Vernon Area?+

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 Mt. Vernon Area?+

A rock hammer, sturdy gloves, safety glasses, and a collecting bag cover the basics here. Add a spray bottle: wet rock shows color and pattern that dry rock hides.

When is the best time to visit Mt. Vernon Area?+

The most comfortable months at Mt. Vernon Area are March to November.

How do I get to Mt. Vernon Area?+

Open the directions link to navigate to 38.30730, -89.13858 in Google Maps. The nearest road is IL 15.

More rockhounding in Illinois

See all 30 Illinois spots →

Open Mt. Vernon Area on the map

Use the RockHoundR app for live land overlays, weather, geology, directions, and saved finds.