Sterling Silver Half Marcasite Open Heart Necklace

Sterling silver marcasite heart necklace. The heart features one side of pavè set marcasites and the other, plain silver. The chain is a sterling silver box chain and marked 925 Italy SU. The pendant is also marked 925 SU and another symbol that looks like a copyright symbol but it's only partially stamped. The necklace is 18" long. Piece shows normal patina