Kofa Thundereggs

These are a bit of an enigma. Some of them have been selling under the name Newberry Springs, but are apparently not (they have a brick red matrix). I bought mine under the name China Creek, which apparently doesn't even exist. They have been turning up in weird places such as ebay UK as basic geodes, untagged of course. The true nature of these stones is still a bit uncertain so don't take it as definite - but Kofa is the best idea yet based on a specimen in Dr Woerner's book and discussion with people in the field. It is perhaps not so surprising though that an Arizona geode should cause such confusion - off the beaten track of the thunderegg hunters but still collected and sold, entering the market from the side as it were.