18k Yellow Gold Plated Sterling Silver Amethyst and Diamond Accent Pendant Necklace , 18" Gemstones may have been treated to improve their appearance or durability and may require special care. The natural properties and composition of mined gemstones define the unique beauty of each piece. The image may show slight differences to the actual stone in color and texture. Amethyst is February's birthstone. All our diamond suppliers confirm that they comply with the Kimberley Process to ensure that their diamonds are conflict free.