What is moissanite and how can I tell the difference between it and a diamond?

Moissanite is a lab-created gemstone based on the structure of natural Moissanite (silicon carbide). On Mohs’ scale of hardness, Moissanite is 9.25 and it has more brilliance, fire and luster than any hard jewel on earth, including diamond.

In the late 1990’s Moissanite exploded onto the jewelry scene and set off a flood of concern over the potential for misrepresentation. Disturbingly, it was found that conventional thermal-based DiamondTesters could not distinguish Moissanite from Diamond. Adding fuel to this concern was a group of British news reporters who took Moissanite to 10 reputable London jewelers for “appraisal” while secretly filming the outcome. Only 1 out of the 10 jewelers secretly filmed correctly identified the Moissanite.

In the early days of Moissanite’s distribution it was not well publicized that it has a very strong double refraction and that any person with a 10x gem loupe and an explanation of what to look for can easily distinguish between the two. While viewing the back facets of Moissanite with a simple 10x loupe, this optical doubling feature is easily spotted. As diamond is a singly refractive gem it will never ever exhibit this effect.