Opal Butte Bed

Opal Butte, located in northeastern Oregon near Heppner, is primarily known for its high-grade precious and common opal, but it has also produced thundereggs—often overlooked compared to the area’s flashy opal seams. Thundereggs from Opal Butte tend to be small to medium in size, with dense rhyolite matrix and interiors that may contain common opal, chalcedony, or agate in pale whites, creams, and light blues. Some nodules show subtle banding or mossy inclusions, though the real draw here is when opal fills the core. While not a major thunderegg locality, the material from Opal Butte offers a unique blend of agate and opal features rarely found together.