Bought this brooch-pendant because I liked the turquoise, plus – it’s a brooch-pendant The seller said it was Royston but I imagine they were going off appearance alone (they didn’t attempt to identify the maker, for instance, and there was zip provenance). But it looks to be by Coolidge Nez (Navajo, d. 1973) according to Mark Sublette’s hallmarks page.
BTW I did a little digging to try to learn more about Coolidge Nez and found some biographical bits and pieces, but alas, no photograph or anything like that. I think he took or was given the Anglo name “Coolidge” after Calvin Coolidge, who was responsible for the Indian Citizenship Act (1924).