I don't know the original trade name for those large thundereggs so I referred them as "Honey Onxy Thundereggs" because the deposit is located right next to the Honey Onyx mines where colorful onyx were mined. The thundereggs are brick-red and in quite large sizes but with narrow agate cores. The colors of the agates are generally gray to white, sometimes lined with red to yellow colors.
  Apparently, the best thundereggs already have been mined out even I did find some whole thundereggs within the decomposed white pertile/tuff bed. I had dug some out but did not find any with wider agate cores and I don't have any means of handling the basketball sized thundereggs besides, there's this BLM's 25-pound limit rule.