This is a Tiffany & Co. Retired 1837 Circle Pendant Necklace in sterling silver (.925). Here is the breakdown of the peace. It features the open circle pendant inscribed with. T & Co and Hallmark stamps, including “925”. It is made entirely from Sterling silver this piece hangs from a delicate silver chain. Part of the Tiffany 1837 collection, which celebrates the brands founding year. This particular design is retired, making it more desirable to collectors and Tiffany fans.