What is Moissanite? The BEST value in a lab created diamond-like gemstone having the look and properties to that of a natural mined diamond with superior brilliance and fire that will never diminish. Moissanite does not look glassy or cloudy like Cubic Zirconia. Moissanite has more brilliance and fire, even more than natural diamonds. Moissanite is so close to a diamond that unlike cubic zirconia and other gemstones, moissanite is also an effective conductor of heat like that of a natural diamond and for this reason when using a diamond tester that detects thermal conductivity, moissanite will pass as a diamond. Moissanite is sold by the diamond size equivalent DEW since Moissanite is just slightly less in actual carat weight than a natural diamond.