The Arizona-New Mexico borderlands are the world’s home of fire agate, a chalcedony with a thin film of iron oxide inside that throws back flashes of red, green and gold like opal when it is ground down just to the fire layer. The Black Hills Rockhound Area and Round Mountain near Safford are public BLM diggings set aside for it, where you chip it from the seams yourself. PUBLIC (BLM rockhound areas), Graham County; hot, so this is not a summer-midday job.
Fire agate
See it on the map
Other places on the map within a couple of hours.