I’m told it’s Zuni, and may be from the Snow White mine in NM. It has initials HJ on the back.
Hubert Johnson.
Search this auction number on eBay. This version, though different from yours, has his full surname in the signature.
112185299147
This is Zuni made. I have never heard of Snow White Mine in NM. Many Zuni artists use Sleeping Beauty Turquoise because of the pure blue color, could be what is used here. Thanks for sharing.