Antique Art Deco Amethyst Diamonds Platinum 18K Gold Ring. The amethyst measures 7 carats with a diamond on each shoulder of the ring. This is a beautiful handmade Art Deco platinum, amethyst, diamonds, and 18K gold ring. Ring size 7-3/4, weight 4.7 grams, the face of the ring measures from top to bottom 13.5 mm, from diamond to diamond across the face of the ring it measures 16 mm wide. The ring is in excellent condition guaranteed to please the new owner. This ring can be worn as a wedding band or an everyday or night ring.