Rock Hunting in Oregon: White Fir Jasper Thundereggs

Central Oregon is the land of the thunderegg rock hunting and a natural magnet to rockhounds. Chances are that if you are planning a trip there, you already know that. But you might want to add a location to your list: search for colorful jasper thundereggs at White Fir Springs.

ABOVE: Yellow-red jasper thunderegg slice by a diamond slab saw.

White Fir Springs is a rockhound-friendly collecting site inside the Ochoco Mountains. There you can dig for fist-sized jasper nodules of pastel yellow, reddish orange, pink, white and tan under the namesake fir trees. These thundereggs have a much different appearance than most of the surrounding region’s agate-filled eggs.

The area is part of a broad and geologically complicated uplifted plateau with the larger area a mixture of Permian, Triassic and Jurassic formations with later fossil-bearing layers above. Add to that Eocene flood basalts and layers of lava, volcanic ash, and mud that covered parts of the area up 1,000 feet deep, and you have the basis for the modern terrain. And the conditions for the formations of these odd thundereggs.

rock hunting: white fir jasper thunderegg

Cut and polished jasper thunderegg from White Fir Springs.

Rock Hunting Thundereggs: How to Get There

From the Route 26 junction with Wildcat Road, turn left onto NF3350 after a short distance. The Forest Service marks the location with a sign about 4 miles from the junction with Route 26. This rock hunting location is about a 1-1/2-hour drive from Bend, Oregon (or at least 6 hours if you ride with me, because I keep stopping to look at stuff).

Once you get into the collecting area, it is not hard to spot the diggings left by many years of visiting rockhounds. The ground is likely covered with bits of broken jasper to further mark the collecting area.

rock hunting: white fir jasper thunderegg

Cutting each thunderegg yields a new surprise.

Rock Hunting Tips

  • A sturdy shovel is helpful here, but you can make do with hand tools in a pinch.
  • The outer appearance of the White Fir thundereggs may not be very impressive, especially when covered in dirt and mud, but you can find some great cutting material here. Look for splashes of color on the outside that may yield a clue to its interior.
  • Be respectful. Once you zero in on the thundereggs, refrain from smashing them. Far too many rockhounds damage perfectly good cutting material for no good reason, and then leave it behind.
  • As always, for backwoods travel, have a safe vehicle with good clearance.
  • Take all the water, food, maps, and supplies that you will need.

This area can be closed by snow in winter, foul weather, or forest fires. For the latest information and conditions for your rock hunting trip, contact Ochoco National Forest ( 3160 NE Third Street, Prineville, Oregon 97754, phone: 541-416-6500). The Forest Service also sells a Central Oregon Rockhounding Map.


Scott Stepanski is a mineral collector and co-author of Gem Trails of Pennsylvania and New Jersey. He also produces the world’s largest selection of mineral and fossil rubber stamps at Butter Side Down Stamps.

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