1/4 Ct Treated Black & White Diamond Necklace By Haley - April 19, 2016 520 1/4 Ct Treated Black & White Diamond Weave Frontal Necklace. This attractive necklace showcases a black and white diamond studded frontal weave design off a flat omega chain. It is secured by a lobster clasp. The total diamond weight is .25 carat.