Lab-grown diamond vs. Simulated diamond: A comparison and guide

Sure, we're a lab-grown diamond company, so we're a little biased. But when it comes to adding a little glam to your life, simulated diamonds like moissanite or cubic zirconia (though typically less expensive) scratch, lack the sparkle of a natural or lab-grown diamond, and can often appear cloudy. While lab-grown diamonds have the same chemical, physical and optical properties as natural diamonds, simulants do not. 

Before we dive into the differences between lab-grown diamonds and simulated diamonds, here's a refresher on lab-grown diamonds. If you're already up to speed, dive into the following section where we explain what simulated diamonds are, how they compare to natural and lab-grown diamonds, and talk about the differences between common simulated diamonds.

What is a lab-grown diamond?

Lab-grown diamonds are diamonds that were grown by scientists in a lab. They share the same chemical makeup as natural diamonds and are optically identical. The most significant differences between natural and lab-grown diamonds are how they're made and how rare they are.

Lab-grown diamonds vs. Natural diamonds

The difference between lab-grown diamonds and natural diamonds is how they are formed. Natural diamonds form below the earth's surface over millions of years, whereas lab-grown diamonds grow in a lab in a few weeks.

What are simulated diamonds?

Confusing a diamond (natural or lab-grown) with diamond simulants happens often to the untrained eye. At first glance, they may appear similar in appearance, but a diamond simulant is not a diamond because their chemical properties are completely different. Diamond simulants, like moissanite, cubic zirconia, and white sapphire, can't compete with a diamond's hardness (which ranks a perfect 10 on the Mohs hardness scale), and they don't have the same optical properties as diamonds. Additionally, simulated diamonds are made from materials like glass or cubic zirconia. Another downside: simulated diamonds will show signs of wear faster and won't be as sparkly as diamonds.

Types of simulated diamonds

There are a number of different types of simulated diamonds, including rhinestones and certain garnets, but the most popular simulated diamonds are moissanite, cubic zirconia, and white sapphire. Here’s a breakdown of how they compare to natural and lab-grown diamonds.


Moissanite started out as a naturally occurring mineral, but natural supply was essentially zilch, so scientists found a way to replicate it in a lab, which allowed for commercial viability. While it might look like a diamond at first glance, it's a much lower grade on color, hardness, and overall quality. 

One of the most significant differences between moissanite and diamonds is their brilliance or fire. Diamonds have a high refractive index, but moissanite has double refraction, meaning the back of the stone's facets reflects twice. To the naked eye, the inside of moissanite may appear blurry, slightly yellow, or gray—and the stone can give off a rainbow prism effect. 

On the Mohs hardness scale, moissanite is a 9.25. This hardness and the rainbow refraction make moissanite a popular choice among people looking for diamond imitations, which is reflected in its pricing. 

Cubic zirconia

Cubic zirconia, most commonly called CZ, is one of the most widely-used and least expensive diamond alternatives on the market, and it is often incorporated into costume jewelry. To make cubic zirconia, powdered zirconium and zirconium dioxide are heated to their melting point and cooled to a solid state. However, because cubic zirconia is a synthetic material made in a lab, it cannot be considered a gemstone.  

On the Mohs hardness scale, cubic zirconia is ranked 8.5 out of 10, and it is often colorless and flawless. However, there is more to the makeup of the stone than hardness and color grading. Cubic zirconia lacks the brilliance of a diamond, which means it doesn't have the same sparkle. Over time and with frequent wear, you can expect cubic zirconia to scratch and yellow; once scratching and yellowing occur, it is not reversible.

White sapphire

White sapphire is related to the popular blue sapphire—it is, just as the name suggests, a colorless sapphire. But, colorless doesn't mean the same in sapphires as it does in diamonds, and white sapphires tend to appear cloudy. While sapphires are naturally occurring and they can also be grown in a lab. Remember how natural diamonds and lab-grown diamonds are chemically identical? Well, the same is true for natural sapphires and lab-grown sapphires, too. 

The biggest drawback to a white sapphire versus a diamond is the color. Colorless sapphire is not nearly as bright or fiery as a diamond and will require frequent cleaning to maintain the near-colorless look. Rainbow flashes found in moissanite aren't an issue with white sapphires, but you do need to look out for dullness to the stone. White sapphires lack the brilliance, fire, and sparkles of light (called scintillation) compared to diamonds. 

On the Mohs hardness scale, a sapphire ranks a 9, making it acceptable for use in rings—a piece of jewelry that gets a lot of wear. 

Sapphires are dense stones, and that can have an impact on how they look. For example, a one-carat diamond will look larger than a one-carat sapphire because of the material density. When you compare white sapphires versus diamonds side-by-side, you'll notice the size differences more and more the bigger the stone is. 

Diamonds vs simulated diamonds: Wear and care

A diamond—both in its natural and lab-grown state—is one of the hardest natural substances on earth and can withstand daily wear and tear. Another plus in the diamond column: the enduring hardness means the diamond’s surface can withstand a better polish than other stimulants, resulting in a more appealing and obvious luster. While many simulants might soon develop scratches and visible abrasions. 

Whew, we know that was a lot of information to take in but we hope you’re leaving with a greater understanding of the benefits of choosing a natural or lab-grown diamond over a simulated diamond.

  • Our environmental commitment

    At Lightbox we are big on transparency and our commitment to reducing the footprint of our stones is a huge part of this. See more on how we grow our stones with 100% renewable energy.

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  • Visit the lab

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  • Lab-grown FAQs, answered.

    Our leading technology means our lab-grown diamonds are among the highest quality you can find. Learn more about the science behind the sparkle with our guide to lab-grown diamonds.