Moissanite is a popular, modern gemstone used as a durable and brilliant alternative to traditional diamonds in fine jewelry. The material exhibits a remarkable fire, which is the gemstone’s ability to disperse light into a rainbow of colors, surpassing that of many other stones. Its visual appeal is matched by its superior hardness and resilience, qualities that make it an excellent choice for daily wear.
The Core Chemical Identity
Moissanite is chemically known as silicon carbide (SiC). This compound consists of a one-to-one ratio of silicon and carbon atoms. The atoms are arranged in a dense crystalline lattice structure, where each atom is covalently bonded to four others. These strong covalent bonds give the material its extraordinary physical attributes, including resistance to scratching. Silicon carbide has a hardness of 9.25 to 9.5 on the Mohs scale, placing it second only to diamond’s perfect score of 10.
The Story of Its Natural Origin
The mineral’s name honors French chemist Henri Moissan, who first discovered it in 1893. He found minute, sparkling crystals while examining rock fragments from the Canyon Diablo meteorite crater in Arizona. Moissan initially mistook the crystals for diamonds due to their brilliance, but he later identified them as a completely new mineral made of silicon carbide. Naturally occurring moissanite on Earth is incredibly rare, existing only in microscopic quantities, typically as inclusions within other minerals or in certain deep-earth rocks from the upper mantle. Because the natural material is so scarce and its crystals are far too small, it is not a viable source for the commercial gemstone market.
Manufacturing the Modern Material
The vast majority of moissanite sold today is a synthetic product, grown under highly controlled laboratory conditions. The raw materials used in this process are high-purity silicon and carbon, which are combined to create the silicon carbide compound. This synthetic route is the only way to produce crystals large and clear enough for cutting into faceted gemstones.
The most common method for crystal growth is a high-temperature technique derived from the Lely process. In this method, silicon carbide powder is placed in a specialized chamber and heated to extreme temperatures, often exceeding 2,000°C. This intense heat causes the solid silicon carbide to undergo sublimation, turning directly into a gas and bypassing the liquid state.
The resulting vapor then migrates to a cooler area within the chamber, where it condenses and slowly deposits onto a small seed crystal. Over several months, this process grows a large, single crystal of silicon carbide, which is then cut and polished into the final moissanite gemstone.