This is a marked Mexico CII 925 sterling silver brooch. It does test positive for sterling silver. It has a modernistic long twisted design. At one end is an oval onyx stone. This is a more contemporary piece dating to the 1980's - 1990's. The closure is a safety locking clasp soldered to the frame with a straight pin stem. There is very minor patina and very minor surface scratches. Size is 5/8 inch in width by 4 inches in length. Weight is 14.7 grams.