Swiss Blue Topaz 5mm Round Diamond Halo Necklace. This classic round halo pendant contains a 5mm center swiss blue topaz with .07cttw of pave set accent diamonds. Comes with a 14k white gold 18 inch chain. This necklace is 14K white gold and diamonds are I/J color and eye-clean SI3 clarity. Designed by Gabriel & Co., also available in yellow gold and rose gold.