Turtle Mountain: Quartz & Agate Rockhounding in Rolette County, North Dakota

Quick details

Access

Permission required

County

Rolette County

State

North Dakota

Nearest road

Bia 23

Coordinates

48.81555, -99.92165

Geology at Turtle Mountain

This spot sits on Fox Hills Formation, mapped as shale and sandstone that formed roughly 100 to 66 million years ago. Tough silica like agate, jasper, and chert typically weathers out of beds like these and collects as float in drainages and on deflation surfaces.

Mapped unit

Fox Hills Formation

Age

100–66 Ma (Late Cretaceous)

Rock types

shale and sandstone

Elevation

1,800 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 Turtle Mountain

Best months: April to October. Typical highs run 80°F in midsummer and 18°F in midwinter, with winter lows near -5°F.

Climate normals: NOAA 1991-2020 monthlies, BELCOURT KEYA RADIO station (8 mi away), adjusted for elevation.

Land & collecting status

Permission required before collecting

Requires landowner or agency permission before any collecting. Do not enter without explicit authorization.

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 Turtle Mountain

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

• QuartzEncyclopedia →
• AgateEncyclopedia →
• ChalcedonyEncyclopedia →