Buchanan Thundereggs
Buchanan Mines, Harvey County, Oregon
Note: Had been labelled as Robins Ranch, Bums Bed, Orange Creek Mountain, & Stinking Water Mountain.

     The mine was originally opened to mine the cinnabar deposits and the thundereggs were considered a nuisance before it became a fee-dig site. When the mine was first opened, several beds of thundereggs with fully silicified hard shells have been found, but as the mining progresses into lower levels (and other beds), those with "rotten" and porous unsilicified shells are becoming more common, hence, "New Buchanan thundereggs". Some thundereggs found there contain reddish cinnabar inclusions while others contain either messy or neat horizontally banded agates and it's tricky to tell which way to cut since they are quite rounded without any ridges showing. The "messy" look resulted from cracking and flaking of each silica when it dried after being deposited (like mud). The site is now closed to collecting.

Click on the pictures to see larger and closer-up pictures.
Rough Appearance: Looks like bunch of bubble clustered together, old ones have green to brown colors while new ones have "bleached" tan color.
Agates are typically messy-looking waterlines sometimes with reddish tints due to cinnabar inclusions.


silicified shells, typical of Old Buchanan eggs
More recent finds with unsilicified shells
bit of reddish spots, possibly cinnabar

Old Buchanan
Old Buchanan identified by white 1st band
and completely silicified shells

Rich in cinnabar inclusions