Antelope: Geode Digging in Wasco County, Oregon

Quick details

Access

Permission required

County

Wasco County

State

Oregon

Nearest road

Antelope Highway

Coordinates

44.90805, -120.73853

Geology at Antelope

This spot sits on John Day/Clarno Group; John Day Formation, mapped as tuffaceous sedimentary rocks, buff, red, green; fossils: roots cavities stems leaves locally well preserved and abundant fossils; rhyolitic to dacitic glass shards; alteration: rocks rich in altered glass and bentonite; mineralogy: feldspar pyroxene amphobile; rock fragments, tuff, green, buff; fossils: roots cavities stems leaves locally well preserved and abundant fossils; rhyolitic to dacitic glass shards; alteration: rocks rich in altered glass and bentonite; mineralogy: feldspar pyroxene amphobile; rock fragments, lapilli tuff, buff; rhyolitic to dacitic glass shards; alteration: rocks rich in altered glass and bentonite; mineralogy: feldspar pyroxene amphobile; fossils: roots cavities stems leaves locally well preserved and abundant fossils; rock fragments, tuffaceous claystone, buff; rock fragments; fossils: roots cavities stems leaves locally well preserved and abundant fossils; rhyolitic to dacitic glass shards; alteration: rocks rich in altered glass and bentonite; mineralogy: feldspar pyroxene amphobile, tuffaceous siltstone, and red; fossils: roots cavities stems leaves locally well preserved and abundant fossils; rhyolitic to dacitic glass shards; alteration: rocks rich in altered glass and bentonite; mineralogy: feldspar pyroxene amphobile; rock fragments that formed roughly 56 to 23 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

John Day/Clarno Group; John Day Formation

Age

56–23 Ma (Eocene to Oligocene)

Rock types

tuffaceous sedimentary rocks, buff, red, green; fossils: roots cavities stems leaves locally well preserved and abundant fossils; rhyolitic to dacitic glass shards; alteration: rocks rich in altered glass and bentonite; mineralogy: feldspar pyroxene amphobile; rock fragments, tuff, green, buff; fossils: roots cavities stems leaves locally well preserved and abundant fossils; rhyolitic to dacitic glass shards; alteration: rocks rich in altered glass and bentonite; mineralogy: feldspar pyroxene amphobile; rock fragments, lapilli tuff, buff; rhyolitic to dacitic glass shards; alteration: rocks rich in altered glass and bentonite; mineralogy: feldspar pyroxene amphobile; fossils: roots cavities stems leaves locally well preserved and abundant fossils; rock fragments, tuffaceous claystone, buff; rock fragments; fossils: roots cavities stems leaves locally well preserved and abundant fossils; rhyolitic to dacitic glass shards; alteration: rocks rich in altered glass and bentonite; mineralogy: feldspar pyroxene amphobile, tuffaceous siltstone, and red; fossils: roots cavities stems leaves locally well preserved and abundant fossils; rhyolitic to dacitic glass shards; alteration: rocks rich in altered glass and bentonite; mineralogy: feldspar pyroxene amphobile; rock fragments

Elevation

2,660 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 Antelope

Best months: February to November. Typical highs run 89°F in midsummer and 44°F in midwinter, with winter lows near 27°F.

Climate normals: NOAA 1991-2020 monthlies, ANTELOPE 6 SSW station (6 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.

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

Found at Antelope

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

• AgateEncyclopedia →
• ChalcedonyEncyclopedia →
• GeodeEncyclopedia →
• JadeEncyclopedia →
• JasperEncyclopedia →