Vintage Topaz Crystal Faceted Glass Clip Earrings

Lovely pair of vintage earrings with just a round single faceted crystal stone set in the center and pronged on four corners. They look so pretty when worn, with lots of sparkle. They are vintage, I would guess from the 1960s or 1970s era. They are not signed. There is some wear to the metal on the reverse. Please see the photos for approximate measurements and details.