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What are Diamond Simulants? Moissanite vs. CZ vs. Lab Diamonds

All white rocks look like diamonds on Instagram. So what are diamond simulants and how can you tell them apart from real diamonds?

Why are there so many google searches for “is my diamond real?” Because when it comes to diamonds, the only thing that’s not confusing is the price. There are a litany of words and types for different kinds of shiny white rocks that range in value from $5 / carat to $5,000 / carat and everywhere in between. Diamond simulants and diamonds look the same in a facebook ad, and to the untrained eye, can even look the same in real life.  So what are diamond simulants and how can you make sure you’re not getting ripped off?


Sensing customer confusion, the FTC cleared some of this up earlier this year by announcing a series of changes designed to address the confusion around lab-grown diamonds and answer the question — what are diamond simulants? In a momentous and long overdue win for lab-grown diamonds, they announced that, “a diamond is a diamond no matter whether is it grown in a lab or comes out of the ground.…” and that they would,“no longer define a ‘diamond’ by using the term ‘natural’ because it is no longer accurate to define diamonds as ‘natural’ when it is now possible to create products that have essentially the same optical, physical, and chemical properties as mined diamonds.” Forbes

They also announced that, “simulants are prohibited from referencing diamonds.”

Unfortunately, a quick search shows many diamond simulant companies using the world lab-grown or lab-grown diamond simulant. So what are diamond simulants, and how can you be assured you’re buying the real thing?


Cubic Zirconia

Have you ever heard of a little something called CZ? Us too! CZ looks almost identical to a diamond except it’s not. CZ is relatively softer than diamond and also more sparkly. As a body double? Perfect? As an engagement ring that will stand up to the wear and tear of everyday life? Not so much. CZ is an 8-8.5 on the MOHS hardness scale which, in our humble opinion, is the lowest you’d want to go for everyday wear.

CZ isn’t graded in the same way that diamonds are. It’s always colorless and clouds / dulls with age.

At Frank Darling, we set our try at home samples with CZ “diamonds” as it’s a practical and economical way to see what a ring will look like before pulling the trigger. Our CZ samples start to dull and look considerable less sparkly after about six months, certainly not a lifetime of wear.

Woman showcasing four placeholder engagement rings made from CZ a diamond simulant.


Moissanite is a fan-favorite, wallet-friendly diamond simulant. It’s durable, low-cost, and has a colorful disco-ball effect that has been known to bring people to their knees.

Moissanite is graded for color and generally comes in three ranges: colorless, near-colorless, and faint hues of color.

While moissanite is absolutely hard enough for day to day wear, registering a 9.25 on the hardness scale, you’ll want to make sure you like the “look” of this diamond double.

A photo of 9 moissanite stones on a womans hand displaying their characteristic rainbow colors.

Simulant Hybrids

Beyond moissanite and CZ, there are several hybrid simulants on the market that use misleading language like “lab-grown diamond simulant“. While they are grown in a lab, they are not lab-grown diamonds. Rule of thumb, if the price looks too good to be true, it probably is. If you see the word simulant, you’re buying a stone that looks like a diamond but may not have the same durability or longevity. After all, looking like a diamond does not a diamond make.


In short, no. Lab diamonds are man-made diamonds that have an identical atomical structure to mined diamonds. They’re made from tiny carbon atoms arranged in the typical diamond crystal structure. They don’t just look like diamonds; they are diamonds, albeit from a lab. Diamond simulants are also made in a lab but sell for a much lower price than lab-created diamonds.

Lab diamonds are graded by IGI And GCAL in the same way as mined diamonds. The GIA grades them slightly differently. You can learn more about why here.


The one thing we do know — every great ring starts with a great setting, regardless of whether you set yours with a mined diamond, lab diamond or diamond simulant. But, picking a setting out online is hard — or at least it used to be. At Frank Darling, all our engagement ring settings are available to try at home, for free. It’s just like our website, but you can touch things.

Get started by selecting your favorite four rings or check out our list of lab-grown diamond rings under $1,000 for inspiration.

We’ll send you sterling silver, size seven, replicas set with 1 carat CZ stones.

Each try at home kit comes with a pre-paid return label, ring sizer, and The Handbook, a practical guide that contains all the information you’ll need to select a diamond. So, what are you waiting for? Let’s get started.