Undoubtedly, Moissanite is one of the most popular diamond alternatives that actually sparkles more than diamonds. Although before answering the main question of how moissanite has such brilliant sparkle, it is necessary to clarify one of the important concepts.
When we talk about gemstone jewelry be it diamonds, moissanite, ruby, sapphire, and many others, the fact is they do not emit light by themselves. The real reason behind having brilliant sparkle is possessing a high refractive index. A high refractive index will cause the reflected light to be stronger and more dazzling. To put it simply, they refract and reflect the surrounding light, so the higher the refractive index, the brighter the reflected light will be.
Therefore, the higher refractive index (also abbreviated as RI) of moissanite allows for better light propagation than other gemstones making it sparkle brilliantly. Gemstones with a higher refractive index tend to reflect more properties of brilliance because the light is inclined at a higher angle while passing through the material. As a result, more light is reflected back to the eye through the crown, instead of traversing straight through the gem. The refractive index of moissanite falls to 2.69 and is the only gemstone having a higher index than that of diamonds.
Additionally, the brilliance and brightness of jewelry are also dependent on its own color, cutting procedure, and cut (such as round, emerald, marquise, radiant, and much more).