For this month’s article, I wanted to clear up one of the biggest misconceptions in jewelry today: the difference between moissanite and lab-grown diamonds.

At first glance, they can appear very similar. Both are beautiful, both are colorless or near-colorless, and both are often used as alternatives to traditionally mined diamonds. But scientifically and structurally, they are completely different gemstones.

A lab-grown diamond is exactly what the name implies — a real diamond created in a laboratory instead of formed underground over billions of years. It has the same chemical composition, hardness, crystal structure, and optical properties as a natural diamond. In fact, even experienced jewelers often require specialized equipment to reliably identify a lab-grown diamond.

Moissanite, on the other hand, is not a diamond at all.

Originally discovered in a meteor crater by scientist Henri Moissan, moissanite is made of silicon carbide rather than carbon. Today’s moissanite is lab-created and designed specifically for jewelry. It is an incredibly durable gemstone and offers impressive brilliance, but it reflects light very differently than a diamond.

This is where most confusion begins.

Moissanite produces more colorful flashes of light — often called a “rainbow” effect. This is due in part to it being doubly refractive. Some people love that fiery appearance, while others feel it can look artificial, more similar to a cubic zirconia when compared to the crisp white brilliance of a diamond, which is singly refractive.

A diamond tends to reflect mostly white light back to your eye with more balance and depth and, to me, moissanite’s scintillation (or sparkle) looks almost blurry rather than sharp like a diamond.

Another important difference is hardness. Diamonds are the hardest known natural substance, ranking a 10 on the Mohs hardness scale. Moissanite is also durable at 9.25, coming just before sapphire at a 9, making it suitable for everyday wear, but it is still not the same material.

Most people don’t realize that while the Mohs scale is numbered 1–10, the gap in hardness between a 9 and a 10 is dramatically greater than the numerical scale itself suggests.

Lastly, price also plays a major role in the conversation. Moissanite is generally far less expensive than both natural and lab-grown diamonds. For some buyers, that makes it an excellent option. Others specifically want the authenticity and prestige of owning a real diamond, whether natural or laboratory-grown.

Neither choice is “wrong.” The most important thing is understanding what you are purchasing and choosing the gemstone that best fits your priorities, lifestyle, and budget.

As a gemologist, I believe education is the most valuable thing we can offer clients. The jewelry industry continues to evolve rapidly, but transparency and honesty should never go out of style.

— Kimberly M. Zander, GIA Gemologist

Owner, K. Zander Jewelry