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Lab Grown Diamonds vs. Moissanite & Other Natural Diamond Substitutes


Those looking for alternatives to mined diamonds often ask us about lab-grown diamonds and other white, colorless gemstones that somewhat simulate the look of diamonds. One popular comparison we get asked about is moissanites vs. lab diamonds: which one is better? And how are they really different? While both are great options for your engagement ring, it’s important to know the differences and similarities, and how they stack up against other colorless gemstones, so you can make the best decision for you.

Moissanite vs. Lab-Grown Diamond: How Do They Compare?

Lab-grown diamonds are grown in a lab from carbon dioxide molecules using cutting-edge technology to create extreme heat and pressure. Using this technology replicates the natural diamond growing process. The result is a man-made diamond that has all the same physical and chemical properties of a mined diamond that formed deep in the earth.

Since they are a complete match from a chemical and physical standpoint, lab-grown diamonds are real diamonds and not diamond simulants. However, because they were grown through a controlled process in a lab and didn’t need to be painstakingly extracted from the ground and move through a lengthy supply chain, they will be much more affordable.

Lab-grown diamonds are graded and given certifications using the same process as mined diamonds. They are cut and polished using the same guidelines and tools. Lab-grown diamonds still rate a 10 on the Mohs Hardness Scale and have the exact same composition as a natural mined diamond. An often-asked question from clients is, “can you tell a lab-grown diamond from a natural mined diamond?” The answer is no. Without a loupe to identify the lasered inscription on the diamond girdle, the two species look identical. (Take our quiz to see if you can tell the difference!)

Moissanite, on the other hand, was first discovered in 1893 by French scientist Henri Moissan. He found particles of the gem in a crater in Arizona that was created by a meteorite that fell to Earth. The crystals are composed of silicon carbide, and because of their extra-terrestrial origin, natural moissanite is incredibly rare.

The moissanite we know today was successfully synthesized for production and is now lab-created. Although both lab-grown diamonds and moissanite are man-made, they have a different chemical makeup and very specific features when viewed in person.

Moissanites are nearly as hard as lab-grown diamonds, scoring a 9.25 on the Mohs Hardness Scale. This makes them very strong and suitable for daily wear. Moissanite has a higher refractive index, helping them exhibit a different kind of brilliance than a lab-grown diamond. It’s typically of a greater intensity and in fiery, rainbow-colored flashes. This effect is particularly noticeable in sunlight and in larger stones.

The grading system for a moissanite is entirely different. Whereas lab-grown diamonds, just as mined diamonds, are graded by the 4Cs, moissanites are graded solely on color since the clarity on moissanites is essentially perfect for every stone. The best quality will be Premium, falling within the G-H color range, and Super Premium, falling within the D-F range. Moissanites will be one of the more affordable diamond simulant options, and their price is based solely on their size and variance between Premium and Super Premium.

What About Cubic Zirconia?

Another commonly known diamond simulant is the cubic zirconia, often called a CZ. Cubic zirconia is a form of zirconium dioxide that’s synthetically made and will be softer than a lab-grown diamond, rating an 8.5 on the Mohs Hardness Scale. This means that the faceted edges on the stone will become more rounded over time with wear and upkeep due to polishing.

Cubic zirconia is made clearer as a result of the synthetic process from which it’s made. But while it is often colorless and equivalent to a D diamond color grade, cubic zirconia is known to fluoresce with a yellowish, beige, or whitish glow when under different UV light conditions.

The biggest benefit with cubic zirconia is that it will be the most affordable option on the market for a diamond simulant. But the big trade-off is with hardness and durability. Any fire and sparkle will naturally dull over time with continued wear.

In our recommendation, cubic zirconia is not a good candidate for engagement rings. They are not strong enough for everyday wear and will rapidly dull in appearance. Cubic zirconia use is a common practice in fashion jewelry and not considered for jewelry of any longevity. For engagement rings, they simply aren’t a viable option, not even for side stones or pave settings.

What About White Sapphire?

White sapphires are often considered as diamond substitutes. They are the colorless version of the sapphire gemstone, so they have many of the same characteristics of a sapphire with a few differences in comparison to a diamond.

White sapphires are a durable choice for an engagement ring, rating as a 9 on the Mohs Hardness Scale. They are the rarest form of natural sapphires as they have no trace minerals to create color in the stone - as what happens to create all other colors of sapphires.

However, in comparison to lab-grown diamonds, the issue with sapphires will always be their inclusions. Due to the corundum mineral its made from and its crystal structure and formation process, inclusions in sapphires can be fairly common. In colored sapphires, the inclusions can actually enhance the look of the stone. For white sapphires, the opposite is true. So finding an eye-clean white sapphire is extremely important so you’re not sacrificing on its brilliance.

When seen side by side with lab-grown diamonds, a white sapphire may appear slightly cloudy or milky. That dulling effect is due to its lack of scintillation - the rainbow-like array of colors given off by a diamond - that simply isn’t present in a white sapphire.

As for price, this is really the best benefit for a white sapphire over a lab-grown diamond. The same as all the other diamond substitutes discussed so far, white sapphires will be much more affordable without losing much on durability.

Overall, in our experience, white sapphires haven’t proven to be a long-term desirable option for engagement rings. White sapphires will dull quickly with daily wear and need cleaning often. They may seem like a more viable option since they are stronger than some other diamond substitutes, but their appearance is likely to be disappointing.

What About White Topaz?

Another fairly popular diamond substitute is a white topaz. The blue version of topaz is the most commonly used topaz in jewelry, but white topaz often appears in conversations for a diamond substitute in engagement rings. As with sapphires, white topaz is the purest version of topaz, lacking all mineral impurities that produce color.

Since white topaz is a natural gemstone, it is likely to have internal imperfections developed during formation. Compared to a white sapphire, a white topaz will likely appear more transparent and almost have a glassy quality to its look. Choosing an eye-clean stone would be important to achieve a clear look with sparkle.

As with a cubic zirconia, white topaz comes in around an 8 on the Mohs Hardness Scale. That means white topaz will be easy to scratch and chip. Another feature of the white topaz is its susceptibility to high temperatures. Over time, this stone is known to gradually lose its sparkle and color, usually due to the accumulation of scratches.

When it comes to price, white topaz is slightly unique. Price will usually lower with an increase in size. The larger a white topaz, the more likely there are to be imperfections that harm its color and brilliance. And over time, the dulling of the stone will be much more apparent in larger sizes.

Conclusions About Viable Substitutes to Mined Diamonds

While there may seem to be a variety of options for colorless, diamond-like gemstones and substitutes, we always recommend that there are only really two viable alternatives to natural mined diamonds: lab-grown diamonds and moissanites. These two stones are the only ones that can stand up to everyday wear while providing the classic beauty of a mined diamond.

For your engagement ring, a lab-grown diamond provides a stunning diamond without the high cost or effect to the environment. Likewise, a moissanite can offer perfect clarity in a lovely man-made stone. Whichever your choice, finding the stone that makes you feel in love with your ring is always the best choice.


Have questions? We're happy to help.



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