At a glance, lab-grown diamonds, moissanite, and cubic zirconia can look very similar.
As alternatives to natural diamonds, they’re often considered by shoppers looking to maximize value within their budget.
While they may share similar properties with each other, since each of these stones has distinct chemical compositions, each of them differs in light performance, durability, and value.
When it comes to making a sentimental purchase, these differences are important to consider. The stone you choose affects not only how your jewelry looks today, but how it withstands time and daily wear.
Understanding what separates these gemstones can help you choose the right one for your needs, whether you're shopping for an engagement ring or a piece just meant for fashion and fun.
In this article, we’ll explain what lab-grown diamonds, cubic zirconia, and moissanite are, highlight what makes each unique, and help you decide which is best suited to your situation.
What is a lab-grown diamond?
A lab-grown diamond is exactly what it sounds like: a real diamond created in a laboratory. It is not a simulant or a “fake” diamond. The chemistry, physics, and optical properties of a lab-grown diamond are identical to those of a mined diamond.
Like natural diamonds, lab-grown diamonds are made of carbon atoms arranged in a crystal lattice structure. As you may recall, graphite, too, is made out of carbon, but because its molecular structure is arranged in sheets, it’s a completely different material.
Since lab-grown diamonds are virtually identical to mined ones, they share the same 3D crystal lattice molecular structure, and thus, the same properties. They’re super durable, and at the same time, interact with light in the exact same way that gives natural diamonds their signature sparkle.
In many cases, distinguishing between lab-grown diamonds and natural ones is extremely difficult, even with a trained eye. Oftentimes, only an inspection through magnification (like a jeweler’s loupe) can reveal the lab diamond’s origin: an inscription indicating laboratory origins, or inclusion patterns that are characteristic of lab-grown stones.
What is moissanite?
Moissanite is a diamond simulant. Unlike diamonds, it’s made of silicon carbide rather than carbon.
Moissanite was first discovered in a meteor crater in 1893 by a Nobel Prize-winning scientist, Henri Moissan; it should be noted that moissanite is extremely rare in nature, and that virtually all moissanite used in jewelry today is grown in a lab.
Moissanite is harder than most gemstones, though still softer than diamond. On the Mohs scale of hardness, it ranks at 9.25 out of 10.
This makes it extremely hard, and is why it’s often touted as a suitable alternative to diamonds for pieces that are meant for everyday wear.
It should be noted, though, that even with its hardness, over time, moissanite can still show wear in ways a diamond typically wouldn’t. Diamonds, the hardest gemstone, are ranked at a perfect 10 on the Mohs scale, which gives them an edge when it comes to long-term durability.
Sparkle-wise, mosisanite handles light differently than diamonds. This is only natural since their chemical composition and makeup are different. Moissanite has a higher refractive index that gives off much more colorful flashes (fire) than diamonds. While some would enjoy this, it’s a common opinion that moissanite’s fire appears artificial.
What is cubic zirconia?
Cubic zirconia, or CZ for short, is another popular diamond simulant.
Like moissanite, CZ exists in nature but only in extremely small quantities. Virtually all cubic zirconia used in jewelry today is grown in a lab. Note that the process for creating CZ is much less costly than it is for moissanite and lab-diamonds, so compared to the other two stones, it’s much more affordable.
With regard to its physical characteristics, Cubic zirconia is much softer than both diamonds and moissanite, ranking about 8 on the Mohs scale of hardness. While this still makes it harder than many natural gemstones, it is not hard enough to resist everyday wear in the way a diamond can.
When brand new, cubic zirconia is extremely eye-clean. It has a bright white appearance with a crystal clear clarity that can sometimes look “too perfect,” especially when compared to a diamond. Its sparkle is also different. CZ can appear very bright and flashy when new, but lacks the depth and balance of light return seen in diamonds. It’s for these reasons, like with moissanite, why the look of CZ is often described as artificial.
Structurally speaking, with a hardness of 8 on the Mohs scale, cubic zirconia isn’t as strong as diamond. While a new cubic zirconia stone can look clear and bright, over time, the gem is known to dull, lose its polish, and accumulate scratches and scuffs.
Because of these limitations, cubic zirconia is generally the better choice for short-term or fashion jewelry rather than pieces meant to last for many years.
Conclusion
When considering options for a natural diamond, lab-grown diamonds, moissanite, and cubic zirconia are all options that one can take. That said, the best option for you depends on what characteristics you’re looking for in your piece.
Durability
Durability is one of a diamond’s defining traits. Their extreme hardness keeps their edges sharp, and surfaces polished even after years and years of wear. This is why lab diamonds are favored for meaningful pieces meant to stand the test of time.
Moissanite is durable compared to most gemstones, but it does not match the long-term resilience of a diamond. Over time, edges can soften slightly, affecting their crisp brilliance.
Cubic zirconia is the least durable of the three, with frequent wear leading to scratches and surface clouding that change its appearance.
If you’re considering a piece to represent a meaningful moment, how long it will last matters. It’s for this reason that how long a piece can last becomes an important factor to take into consideration.
Appearance and light performance
Although lab-grown diamonds, moissanite, and cubic zirconia can look similar at first glance, their visual differences become clearer upon closer inspection.
Lab-grown diamonds have the same balanced light performance as mined diamonds. Their sparkle appears sharp and natural across many lighting conditions.
Moissanite, with its higher refractive index, creates stronger flashes of rainbow color. While some would like this, compared to a diamond, it does look artificial.
Cubic zirconia does appear extremely clear and bright when new, and it does have more fire than diamonds. That said, like moissanite, these pronounced qualities can look artificial. Furthermore, due to being less hard, the stone dulls with regular wear.
While each stone has its own visual character, only lab-grown diamonds fully replicate the look and performance of a diamond.
Choosing the right stone
With the rise of lab-grown diamonds, the accessibility gap between diamonds and simulants has narrowed significantly.
Where in the past, clients may have chosen moissanite because they felt diamonds were out of reach, nowadays, with lab-grown diamonds, they can get a real diamond at a much more affordable price point.
While moissanite and cubic zirconia are still chosen by those prioritizing the lowest upfront cost or a particular visual style, they are no longer the only affordable alternatives.
Fine jewelry is often intertwined with major moments — engagements, anniversaries, and personal milestones.
When it comes to commemorating these special occasions, durability, beauty, and permanence matter. Lab-grown diamonds offer all three, while simulants are better suited for fashion or short-term wear.
If you’d like to see these differences firsthand, we’re happy to walk you through them. We invite you to our Milwaukee showroom, where for over 59 years we’ve been helping clients choose the perfect gemstones for their cherished keepsakes. Whether it’s lab grown diamond or a natural one, we’re the fine jewelers that Milwaukee has come to know and trust.
