... My two partners and I have owned these claims ( see Fallen Tree Mine also - red.) for nearly 2 years now, before then it was held by the Mt Hood Rock Club.
The claims are located high in the Ochoco Mountains approximately 20 miles Northeast of the town of Prineville. They are adjacent, with a small annual creek running between the diggings. The elevation of the claims is around 4,500 feet, and the landscape is dotted with large boulders and Ponderosa pine trees. The scenery is beautiful! The roads that lead to the claims are dirt, and are closed much of the winter due to snow, so the digging season runs from about late April into October. The spur road that goes into the Fallen Tree is very muddy, except in a fairly dry summer, and full of holes and so is not recommended for regular vehicles.
... The eggs from Killer Green usually have a grey-green matrix, though sometimes it can be a very nice dark shade of green. These eggs typically have quartz centers, either solid or open geodic cavities. Occasionally they may have agate centers of white to light blue color, with or without fortification banding, and also can have mossy inclusions. They may contain pockets of soft zeolite that immediately soak up the oil from the diamond saw upon cutting. There are sometimes double or triple eggs that have a core of agate in one part and a core of quartz crystals in another section. I have also seen eggs from here with beautiful green tubes running throughout the core. These tube eggs are very rare and desirable.
... My partners and I hope to work the claim for several years and bring to light many more beautiful specimens. We work the claim by hand so as not to destroy many eggs, but that also makes the work slow and the output from any particular trip may be only a few gallons. The host material at both claims ranges from sticky clay to hard rock, so the digging requires sharp tools and much patience. Of the rough eggs that are cut, perhaps only 10 percent will be nice enough to sell or keep in our collections.
extract of the article from Mark Ketsdever, Hillsboro, Oregon, 2007 :”Thunderegg Agates of the Ochoco Mountains, Oregon, USA”