Polished Thunderegg Half - 298g

A nice, classic example of a 'thunderegg' cut in half with a polished front. 

A thunderegg is a naturally formed nodule that develops within volcanic ash layers, most famously found in Oregon but also discovered in other parts of the world. On the outside, a thunderegg can look like an ordinary round rock, but when cut open and polished, it reveals a core often filled with jasper, opal, or in this case, agate, and chalcedony.

These formations began millions of years ago when gas bubbles or cavities formed in rhyolitic lava. Over time, silica-rich fluids seeped into those cavities and slowly crystallized, creating the colorful, patterned interiors that make each thunderegg completely unique.

Thundereggs are Oregon’s official state rock and are prized by collectors for their variety of colors, patterns, and the element of surprise they hold—no two are ever the same.

83x77x38mm

298g