Calapooia River

Thundereggs found in the Calapooia River area of western Oregon are relatively rare but notable for their waterworn appearance and unique river-polished surfaces. These nodules are typically small to medium in size, with agate interiors that range from milky white to soft gray, sometimes showing hints of blue or faint banding. Unlike thundereggs from eastern Oregon’s dry beds, Calapooia specimens are often smoothed by years of river transport, making them appealing both as natural display pieces and for cutting. Their rounded, well-worn exteriors and subtle internal features make them a distinctive find in the Willamette Valley region.