14kt yellow gold tsavorite diamond signet ringThis 14K yellow gold O Thongthai tsavorite diamond signet ring is cast with a wide, polished band. The hexagonal top plate is inlaid with black onyx surrounded by a ridged border, with its centrepiece a green tsavorite framed with pav white diamonds. O Thongthai makes jewellery fit for a Disney villain. While they may not be the kindest, many of them do have an enviable sense of style.