One is pure carbon, the other is carbon and silicon. Such is the chemical nature in Moissanite vs. diamond. Diamond, of course, is pure carbon. Moissanite is chemically referred to as silicon carbide. But when considering Moissanite vs diamond, this may surprise you: Taking Moissanite vs diamond, Moissanite is actually much, much rarer. Basically the only source of Moissonite we have here on planet Earth comes from meteorites – bits of rock that crash here every so often from outer space, and even that source is extremely rare.
So, in the Moissanite vs diamond equation, why, exactly, is diamond so much more expensive and desireable whereas Moissanite is considered the fake, the imposter? There are several answers. I’ll start with the simplest. The Moissonite that we have today is all synthetic, including Moissonite jewelry that serves as simulated diamond. The process of synthesis of Moissanite is not difficult, nor is it expensive. But to go a bit deeper, if we take Moissanite vs diamond in terms of simplicity, Moissonite is a lattice of two atoms – carbon and silicon, both of the same group in the periodic table of elements, both having four valence electrons, which makes it easy for them to bond. The fact that they both have four bonds to fill also makes their lattice extremely hard. However, Moissanite vs diamond, diamond is harder because its bonds are perfectly even. Moissanite has a more uneven bond structure because carbon is slightly more electronegative than silicon, pulling the bonds slightly more toward the carbon atoms than the silicon atoms. This makes Moissanite slightly softer than diamond, so Moissanite vs diamond as far as hardness goes, diamond wins. Moissanite is 9.5 on the hardness scale. Diamond is a perfect 10.
Another thing that may surprise you in the Moissanite vs diamond fight is that Moissanite is actually far superior to diamond when it comes to its heat resistance. Diamond begins to burn at 800 °C. Moissanite, or silicon carbide, can withstand temperatures of up to 1800 °C. The best way to test for Moissanite vs diamond is a fluorescence test under ultraviolet light. Moissanite reflects slightly green or yellow. Diamond does not.
But the most elegant reason that in the Moissanite vs diamond fight, diamond is always preferred for jewelry is simply that diamond is a product of our home planet, whereas Moissonite simply is not. It is artificial. Jewelry is art. Art is a reflection of nature. Moissanite is therefore, not really jewelry.

