12 ct round 15 mm Better than today's CZ’s, better than Moissanite. Our Secret Jewelers stones were made over 25 years ago with much higher standards than today's diamond imitations. Each stone is equivalent to an E color diamond and are internally flawless. Their brilliance and fire is a testimony to their craftsmanship and longevity. They will last hundreds of years without discoloration. These stones are better than Moissanite which is a generic material made for commercial purposes. Moissanite's refractive index is much higher than a diamond and they cast a yellow tone which makes they look fake to professionals. Moissante can be very expensive and they will not fool a jeweler by eye or loupe. Our stones as you can see on the attached video fools jewelers, let alone your friends. Compare price and appearance ours is superior.