The "THAMES" London Blue Topaz and Diamond Ring from Lika Behar's Amazing Mesmerizing Gems collection is crafted with 24K gold and oxidized silver for a beautiful statement piece. The marquise-shaped London Blue Topaz center 6x12mm weighs 2.12 carats and 28 round diamonds of 0.19 carats encompass it. This exquisite ring measures 18.79x12.79x3.50mm and weighs 5.3 grams, with a size of 6.1/2.