Wallace: Moss Opal Rockhounding in Wallace County, Kansas

Quick details

Access

Public area

County

Wallace County

State

Kansas

Nearest road

County Road Wa S-26

Coordinates

38.84891, -101.59254

Geology at Wallace

This spot sits on Ogallala Formation, mapped as arkose that formed roughly 23 to 5 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

Ogallala Formation

Age

23–5 Ma (Miocene)

Rock types

arkose

Elevation

3,570 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 Wallace

Best months: February to June. Typical highs run 91°F in midsummer and 44°F in midwinter, with winter lows near 14°F.

Climate normals: NOAA 1991-2020 monthlies, WALLACE station (4 mi away), adjusted for elevation.

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 Wallace

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

• Moss OpalEncyclopedia →