Vintage Turquoise and Sterling Silver Screw back Earrings - Mid-Century

Screw back earrings were in their heyday in the early1900's, so I believe these hand-crafted Southwestern-style turquoise earrings probably do not date to later than the early 1950s, and they might be much earlier. The stones are a vibrant blue turquoise with a very faint black matrix. The style suggests they might be Native American but they are not signed. They are marked "STERLING" on the ends of the screws. Very good pre-owned condition. There is some tarnish but I leave serious polishing to the discretion of the buyer. $90 for all three or $28.00 a piece.