The Muggins Mountains is a Mountain range in southwest Arizona, east of Yuma and northeast of the Gila Mountains. It contains a wilderness area with the same name.
Jeffrey Anderson is describing this location on his website dwarve´s earth treasures:
“....Somewhere in the Muggins Mountains have produced very large reddish brown aphantic thundereggs usually with narrow agate cores. Often, the rhyolite shells have to be broken in order to extract the agate cores. The agates are dark colored and widely contains brown to yellow moss-like and plume inclusions. Those with very obvious plume structures are desired from that location for lapidary purposes....”