Rimrock Lake

The Rimrock Bed, located in central Washington near Rimrock Lake, is a scenic thunderegg site known for producing nodules with muted but attractive agate interiors. These thundereggs often feature soft grays, whites, and light blues, sometimes with subtle moss or dendritic inclusions. The rhyolite matrix is typically dense and weathered, with eggs ranging from small to medium in size and usually solid enough for cutting. While not as widely collected as some eastern Washington localities, Rimrock thundereggs are appreciated for their delicate patterns and the striking alpine setting in which they’re found.