This is a lovely and timeless brooch by Catamore. Catamore was a jewelry company that was in business from 1942-1981. They made higher quality jewelry that was usually 12K GF or sterling silver. This particular pin was created from 1/20 12K GF and eight black onyx cabochons. The onyx settings are also interesting because they have decorative edges on the bezels.
This pin is in fabulous condition with no wear etc. worth mentioning. Truly a circle pin worth wearing or having in your collection.