Moissanite is a compound of silicon and carbon. The French geologist Henri Moissan discovered it while mining in the Arizona Territory in 1893. (Moissan also made a number of attempts to synthesize diamonds out of other forms of carbon.) Small amounts of moissanite have been found in meteorites. The mineral does not occur in any abundance in nature, and so it only the synthetic forms which are widely used commercially.
1) Moissanite vs diamond: appearance
Moissanite can look deceptively like a diamond. Both minerals are essentially colorless (but see below). But moissanite has a higher refractive index— a measure of the speed of light through that medium (2.65, compared to 2.42 for diamond)— which gives it a higher degree of “sparkle.” This is really the main difference in appearance between them, but it is difficult to detect unless one really examines the stone very closely, or if the specimen is a rather large one. Another is that moissanite is naturally green.
2) Moissanite vs diamond: hardness and cost
The two minerals have about the same hardness (9.5 vs. 10), and so both are useful for experiments involving high pressure. But anvils made of diamond are much too costly to be used for experiments on a large scale, and that is an area where synthetic moissanite steps in.
Moissanite is, more generally, much cheaper than diamond. As a comparison, a ½ carat diamond costs $1,422, whereas the same weight of moissanite costs $114— a difference of $1,308! So for all these reasons, one can buy jewelry of the same quality as diamond gems for less and with more sparkle. And manufacturers keep the cost down by pricing the mineral by size and not by grade, so they can sell more of them.
3) Moissanite vs diamond: heat conductivity and other properties
Diamond and moissanite also conduct heat to about the same degree. Moissanite has a higher toughness— the ability to bend and stretch without breaking— than diamond. It is also superior in the following other properties, not only to diamond, but to other hard minerals as well— cubic zirconia, ruby, sapphire, and emerald:
- dispersion (fire), or the fraction of atoms exposed to the surface— .104 vs. .044
- luster index— 20.4% vs. 17.2%
Natural moissanite is so scarce that it cannot be used even for jewelry. The manufacturing company Charles & Colvard is the only enterprise in the world that has learned how to work with these rare specimens. And they hand- cut their gems very precisely. As they say in their Youtube video, “Moissanite is not a diamond stimulant, but rather a unique jewel unlike any other.” And people all over the world are realizing that fact, and more and more women are buying moissanite jewelry for each other: mothers buying for daughters, aunts for nieces, and so on.
Finally, it must be realized that a diamond investment is an “illiquid asset”— meaning that is is very difficult, if not impossible, to sell a piece of that mineral when one is in need of cash. So the debate on Moissanite vs Diamond lives on!