What Is Moissanite?

Moissanite is a silicon carbide gemstone, originally discovered in a crater which resulted from a meteorite crashing into the Arizona landscape. Discovered in 1893 by French chemist Henry Moissan, natural moissanite is incredibly rare, so today the gemstone is created in a laboratory, resulting in sparkling, conflict-free stones that cost a fraction of diamonds, but are virtually indistinguishable from them. In fact, the Gemological Institute of America (GIA) has said that moissanite is “much closer to diamond in overall appearance and heft than any previous diamond imitation.”

Because it is very difficult to tell a diamond and a moissanite apart, moissanite makes for a common, and brilliant, diamond alternative. While it is almost impossible to differentiate between the two gemstones, there are several significant differences between the two.

The 4 Cs

The GIA, which is the largest, most respected nonprofit source of gemological knowledge in the world, judges diamonds on the four Cs: color, cut, clarity and carat weight. However, due to their differences in composition, moissanites are only judged on their color, because the cut and clarity of moissanite are fairly consistent.


Diamonds are judged on a color scale ranging from D to Z, with D-grade diamonds being the most desirable. Diamonds graded D–F are classified as “colorless,” while those graded G–J are classified as “near colorless.” All moissanites’ color are similar to either the colorless or near colorless rating of diamonds, although some larger moissanites can display a slight yellow or gray color in certain light.


When it comes to gems, most people think the term “brilliance” is just a type of vague descriptor that indicates the gem’s “shininess.” However, it is actually a technical term that specifically refers to how light reflects from the interior of a transparent gemstone, and it is enhanced by the cut of the stone. Moissanites have more brilliance than diamonds, because they have a higher refractive index. While moissanites can range from 2.65–2.69, diamonds have a refractive index of 2.42. The higher the refractive index number, the more brilliance a gem displays.


Fire is another term in gemology that is often misused. Also known as dispersion, “fire” refers to a gem’s ability to split white light across the spectrum, like a prism. This happens when different wavelengths of light are refracted by the internal facets of the stone. Diamonds are famous for their fire, but moissanite actually has a higher fire rating at 0.104, as compared to diamonds, which are rated at 0.044.

The combination of brilliance and fire, along with other characteristics, such as luster and scintillation, give a stone its overall sparkle. Because of the differences between the gems’ cuts and refraction levels, the two types of stones sparkle a bit differently. Some people compare moissanite to a disco ball because of the way the rainbow light flashes around the gem. This effect isn’t a foolproof way to differentiate between a moissanite and a diamond though, as expertly cut diamonds will also sparkle quite a bit.


Diamonds are the hardest naturally occurring substances on Earth. They score a 10 on the Mohs Scale of Hardness, which measures resistance to surface scratching. Moissanite isn’t quite as hard, receiving a 9.25 on the scale. However, since it’s nearly as hard as a diamond, it will also last a lifetime, even with everyday wear.


Moissanites weigh about 15 percent less than diamonds, so stones that are visually equivalent in size have different weights. Because of this, moissanite is usually sold by length and width (in millimeters), as opposed to carat weight.


Although lab-created diamonds are less expensive than natural diamonds, they are still more expensive than moissanite. While gem quality diamonds sell for thousands, and even tens of thousands, of dollars, a moissanite stone of similar size would only cost a fraction of that price. There are other “costs” to consider when it comes to selecting a gem as well: environmental impact and ethical sourcing. Lab-created moissanites have smaller carbon footprints than natural diamonds, and have easily traceable origins. This makes choosing moissanite a more conscientious option, as well as a less expensive one.

While history tells us that the first diamond engagement ring was given to Mary of Burgundy by the Archduke Maximilian of Austria all the way back in 1477, the truth is that diamond engagement rings weren’t popular in America until the late 1930s, when DeBeers Consolidated Mines, Ltd. discovered a cache of diamonds in South Africa and hired a savvy ad agency to create one of the most successful ad campaigns of all times.

Nowadays though, people are aware of the inherent problems associated with diamond mining, and are seeking out diamond simulants that have all the sparkle and shine of the real thing, without any of the drawbacks. Of the available diamond alternatives, moissanite is far superior to its competitors in terms of appearance and verisimilitude, which is why its popularity is expected to continue to grow in the future.