Seta gold tone ring with black glass and crystal accent size 7

Pretty cocktail ring with a large oval black cabochon set in gold tone metal. Metal wraps across the front of the cabochon, and has a small colorless crystal accent in the middle. Size 7, as shown in mandrel photo. No known flaws. Marking appears to say SETA. Not attracted to a magnet, so possibly a gold plate over brass or silver. No markings to indicate metal content. Note: I've seen this exact ring listed elsewhere as being black onyx, but on my Presidium Gem Tester it registers as glass, not quartz.