Dexter: Chert & Blue Agate Rockhounding in New Madrid County, Missouri

Updated June 2026

Dexter is a mapped rockhounding spot in New Madrid County, Missouri. Reported finds include chert, blue agate, gray agate, pink agate, white agate. Below: coordinates, access notes, nearby spots, and trip-planning links.

Quick details

Access: Public area
County: New Madrid County
State: Missouri
Nearest road: MO D
Postcode: 63870
Coordinates: 36.61429, -89.96237

Geology at Dexter

This spot sits on ground mapped as clay, silt, and sand that formed within roughly the last 12,000 years. Gravels like these concentrate whatever survives the river: agate, jasper, and other tough silica typically show up as rounded, waxy stones.

Age: < 1 Ma (Holocene)
Rock types: clay, silt, and sand
Elevation: 280 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 Dexter

Best months: September to June. Typical highs run 92°F in midsummer and 46°F in midwinter, with winter lows near 27°F.

Climate normals: NOAA 1991-2020 monthlies, MALDEN MUNI AP station (2 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 Dexter

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 Dexter.

Across the state line from Dexter

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

Dexter FAQ

Where is Dexter?+

Dexter is in New Madrid County, Missouri, at 36.61429, -89.96237. Nearest road: MO D.

What rocks and minerals can you find at Dexter?+

Dexter is reported to produce Chert, Blue Agate, Gray Agate, Pink Agate, White Agate.

Is collecting allowed at Dexter?+

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 Dexter?+

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 Dexter?+

The most comfortable months at Dexter are September to June.

How do I get to Dexter?+

Open the directions link to navigate to 36.61429, -89.96237 in Google Maps. The nearest road is MO D.

More rockhounding in Missouri

See all 94 Missouri spots →

Open Dexter on the map

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