i can’t speak to the mine origin of the stones, but the screwback mechanism is very common and was used up through the 1940s or 50s i think. It’s a commercial finding that you could buy in jewelry supply stores. The earrings look legit to me, but I can’t authenticate as Zuni - I believe Navajo makers also did cluster work. hopefully someone more knowledgeable will come along.
Aw thank you! I totally agree. I will be selling these in my shop as I have gaged ears and cannot wear normal earrings. Whomever snags these will be a lucky person for sure