Whiteclay: Agate & Chalcedony Rockhounding in Sheridan County, Nebraska

Quick details

Access

Permission required

County

Sheridan County

State

Nebraska

Nearest road

Elder Drive

Postcode

69360

Coordinates

42.99381, -102.56284

Geology at Whiteclay

This spot sits on White River Group, mapped as clay that formed roughly 34 to 23 million years ago. Petrified wood typically travels as tough float, and worked gravels like these are exactly where weathered pieces tend to collect.

Mapped unit

White River Group

Age

34–23 Ma (Early Oligocene to Late Oligocene)

Rock types

clay

Elevation

3,280 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 Whiteclay

Best months: March to November. Typical highs run 89°F in midsummer and 37°F in midwinter, with winter lows near 12°F.

Climate normals: NOAA 1991-2020 monthlies, PINE RIDGE AP station (3 mi away).

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 Whiteclay

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

• AgateEncyclopedia →
• ChalcedonyEncyclopedia →
• JasperEncyclopedia →
• Petrified WoodEncyclopedia →