That's a nice one, congrats!
My grandparents always said that type was Apache. I've found many of them around Benson, St. David, Tombstone and Elfrita.
Btw, I was born in Florence.
The frame of pottery came from Gila County AZ, alot of culture out that way Anasazi, BI'm not sure. I'm thinking Hohokam. I usually find small one's. This one is the largest I've found.
Looks natural to me, Mother Nature is quite the artist...