Giant 40ct Amethyst Oval Pendant In 18 Karat Yellow Gold Over Sterling Silver, With 24 Inch Chain Amethyst is a member of the quartz family. Amethyst sold by SuperJeweler is natural and not treated. Amethyst is a member of the quartz family. Amethyst sold by SuperJeweler is natural and not treated. Amethyst is a member of the quartz family. Amethyst sold by SuperJeweler is natural and not treated. Amethyst is a member of the quartz family. Amethyst sold by SuperJeweler is natural and not treated.