“Priday” or “Plume Agate” is a very rare agate found many years ago on the Priday ranch outside Madras Oregon. Long gone are the digging opportunity’s for this agate found in thunder eggs. You will find moss with rich browns patterns and in some cases plume patterns which become more valuable all laced within a beautiful agate matrix.
Wikipedia says, "A thunderegg (or thunder egg) is a nodule-like geological structure, similar to a geode, that is formed within a rhyolitic lava flow."
Thundereggs are rough spheres, most about the size of a baseball - though they can range from less than an inch to over a meter across. They usually contain centers of chalcedony in the form of agate, jasper or opal, either uniquely or in combination. Also frequently encountered are quartz and selenite crystals, as well as various other mineral growths and inclusions. Thundereggs usually look like ordinary rocks on the outside, but slicing them in half and polishing them may reveal intricate patterns and colors. A characteristic feature of thundereggs is that (like other agates) the individual beds they come from can vary in appearance, though they can maintain a certain specific identity within them.
Phoenix
42°