Vintage brass diamond shaped brooch with guilloche enamel rose and black border. Manufacturer is unknown; the patent number on the back of the pin is for the clasp. I believe this is brass and not brass plated, as it is non-magnetic. It measures apx 1 3/4" x 1 1/4" and is in very good pre-owned condition. There are a few scratches to the finish seen with a loupe, but as there is no loss of color, they blend in. Please note that what looks like wear to the left side of the black border in the photos is merely reflections.
Vintage Guilloche Enamel and Brass Rose Brooch