What Is Refractive Index? Why Moissanite’s 2.65 Matters

Refractive index is a physical measurement of how much a material bends light as it passes through. It’s the number that determines how much fire and brilliance a stone throws off, not marketing language, an actual optical property that can be measured in a lab.

Moissanite’s refractive index is 2.65. That’s higher than any gemstone commonly used in fine jewelry, including diamond, which measures 2.42. The higher the number, the more light gets bent and split inside the stone before it reflects back to your eye as sparkle and color flash.

This is one of the reasons moissanite reads brighter in person than people expect. It isn’t imitating anything. It’s a distinct crystal with its own optical signature, and that signature happens to be one of the most brilliant in the world.

Full guide: Is Moissanite Real? A Straight Answer, and What to Say When Someone Asks