This early 20th century pin was made by the Plainville Stock Company,and is marked PSCO on catch. The patterned area around the bezel is reminiscent of many 19th century pieces. The cabochon top purple glass set, with the color of amethyst, has a faceted underside, rather unique for a piece of early 20th century jewelry. The finish appears to be plated, with some discoloration on the back. Slight bend on the rim, shown in photos. The pin is rather petite, measuring about 1" x 3/4". The glass set measures about 5/8".