Moissanite

Synthetic moissanite is an artificial gemstone that is often used as a simulant for diamond. It is an incredibly dispersive material, meaning that it exhibits a high amount of fire and brilliance, similar to that of a diamond. It was first introduced as a gem material in 1998, and is the transparent form of carborundum. Synthetic moissanite is typically off-white, with a yellowish hue.

Synthetic moissanite is doubly refractive, and this can be seen looking through the stone through the kite facets, to reveal a doubling of the pavilion facets. This is because light is split once it enters the stone, travelling in two different speeds through the hexagonal crystal structure, resulting in this telltale optical feature.