Rockville: Opalized Wood & Agatized Wood Rockhounding in Malheur County, Oregon

Plan your visit

Confirm rules before collecting

County

Malheur County

State

Oregon

Nearest road

Succor Creek Road

Coordinates

43.32366, -117.11969

Coordinates are approximate. Confirm the exact ground in the RockHoundR app, where land overlays show which agency manages the area.

Land & collecting status

Confirm rules before collecting

Land status here is not confirmed. Verify with the managing agency before collecting, federal, state, and tribal rules differ.

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.

Best time to visit Rockville

Comfortable months (45 to 90°F highs)

Best months: March to November. Typical highs run 90°F in midsummer and 38°F in midwinter, with winter lows near 21°F.

Climate normals: NOAA 1991-2020 monthlies, ROCKVILLE 5 N station (3 mi away), adjusted for elevation.

Geology at Rockville

This spot sits on Oregon-Idaho Graben; Upper member, mapped as vitric tuff, white, pale yellow; fossils: vertebrates fossils, bentonitic claystone, grayish green; fossils: vertebrates fossils, tuffaceous siltstone, and pale yellow that formed roughly 23 to 5 million years ago. Volcanic rock like this is classic geode and thunderegg country: gas cavities in the old flows can line themselves with quartz or agate over time.

Mapped unit

Oregon-Idaho Graben; Upper member

Age

23–5 Ma (Miocene)

Rock types

vitric tuff, white, pale yellow; fossils: vertebrates fossils, bentonitic claystone, grayish green; fossils: vertebrates fossils, tuffaceous siltstone, and pale yellow

Elevation

3,850 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.

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.

State guidance last verified: April 1, 2026

• BLM Oregon/Washington, Rockhounding & mineral material
• Oregon Department of Geology and Mineral Industries (DOGAMI)
• Oregon Parks and Recreation Department, beach collecting rules
• Community submissions reviewed against published agency rules