The Brogan Ranch, located in Malheur County, Oregon, is a classic thunderegg site known for producing large, durable nodules with richly colored interiors. Thundereggs from this location often contain bold agate in shades of red, orange, and brown, frequently accompanied by moss, plume, or jasper-like inclusions. The rhyolite matrix is typically dense and tan to reddish, with a rugged exterior that conceals the vibrant patterns inside. Brogan Ranch material is especially valued for its solid structure, making it excellent for slicing and polishing. Though not as widely known as some neighboring beds, it remains a favorite among cutters and collectors looking for strong contrast and earthy, high-desert beauty.
Rocks of the Cascades – Thundereggs, Tools & Tradition