Diamond vs. Cubic Zirconia: How to Tell the Difference?
cut diamonds and cut cubic zirconia side by side

Diamond vs Cubic Zirconia: How To Quickly Spot Their Differences?

Looking at both stones under natural light, diamonds show a strong white light (the "diamond's fire" or "brilliance") whereas cubic zirconia gives off much more colored lights (the "rainbow effect") as cubic zirconia has a lower refractive index and higher dispersion rate than diamonds.

Another difference is that cubic zirconia is heavier than diamonds and of course... way cheaper. Why is that?

READ: The Woman Shaking Up the Diamond Industry

Diamonds vs. Cubic Zirconia

Cubic zirconia is a lab-created product of zirconium oxide, and it’s technically known as a diamond simulant. That is why it is known as a metaphor for fakeness. But, one probably shouldn’t take this for granted and should be ready to mount a good comparison between cubic zirconia and its expensive counterparts.

If a diamond is a girl’s best friend, what is cubic zirconia? A second-best friend? A helpful aunt or a wise neighbor? Is a cubic zirconia engagement ring worth something?

Whichever path you take, it’s important to at least know what you’re getting into. You can buy cubic zirconia, but at least do it in full knowledge.

blue diamond on black background

Diamonds and What They’re All About

First off, there are two major types of diamonds: mined and lab-made. Mined diamonds are what a person thinks of as “natural” diamonds. They are taken out of the Earth. But let’s get a bit more detailed. First, without getting too complex, one part of the Earth’s crust is called the mantle. This part is deep—we mean nearly a hundred miles—below the surface. Diamonds are initially formed there.

They get near the Earth’s surface through intense pressure by way of volcanic eruptions. These eruptions form something called kimberlite or lamproite pipes that can also be thought of as diamond mines. Diamonds are made of the single atom carbon, which is part of what makes them so special. The arrangement of carbon atoms in diamonds gives them their incredible hardness. For example, graphite is also made of carbon, but is extremely soft. The difference between diamonds and graphite is how the atoms are arranged.

As a side note, if you’ve heard that diamonds (or cubic zirconia) come from coal, that is a myth.

Anyway, that’s the basics of the mined diamond.

What about the lab-created diamond? Well, remember when we talked about these volcanic eruptions? They are what bring diamonds from the core of the Earth up near the surface. What is present in volcanic eruptions is intense heat and intense pressure. How could humans harness such extreme conditions?

In the 20th century, scientists figured out how to do just that. This is where lab-created diamonds come in. American and Swedish researchers found out, in the 1950s, how to turn carbon and molten iron into diamonds in a lab. For a while, these weren’t good enough to put on a nice ring or to wear on a necklace. But eventually they got to that point. Now, most cheap diamonds you get were created in a lab. But this doesn’t really make cubic zirconia synthetic—actually cubic zirconia come from natural materials, just as mined diamonds do.

They just get a boost from technology.

The Value of Diamonds

First, for a couple of scientific factors. The Mohs scale measures the hardness of gems and stones. Diamonds score a 10 out of 10 and are the hardest objects on Earth. Famously, they can cut glass, and they have a mysterious ability to maintain their incredible shine. They reflect light in a brilliant and amazing way.

Because of the durable and long-lasting quality of these ultra-hard stones, diamonds have become synonymous with eternity. That was helped along by an ad campaign for De Beers, a South-African diamond cartel, with the slogan “Diamonds are Forever.”

This basically launched the idea, which took firm hold in society, that if a man had enough commitment, he’d buy a diamond as an engagement ring. If he didn’t buy a diamond, his commitment wasn’t strong enough.

This gave rise to the idea that a more valuable prospect for a husband was one who bought a more expensive and larger diamond. Even if a particular woman doesn’t need a bigger diamond per se, and would never judge a lover that way, diamonds are standard for engagement rings.

This in turn has cemented the reputation of diamonds as not only a gorgeous and lovely item, but a very culturally-significant one.

READ: You Won’t Believe Where Diamonds Come From

Cubic Zirconia vs. Diamonds: How Cubic Zirconia is Different from Diamonds

Something formed millions of years ago in the Earth’s mantle is pretty amazing. In fact, some diamonds were formed from the impact of asteroids. What an amazing thing to wear on one’s ring finger, in addition to just how pretty they are!

Cubic zirconia doesn’t share that sort of origin. However, these days, a lot of diamonds are created in a lab anyway, and that might level the playing field just a bit. So where does cubic zirconia come from? Its origin is zirconium oxide.

Zirconium oxide is a white crystalline powder. One use of this element is in glazes and ceramic colors. When it is melted at an extremely high heat, it creates crystals, which are then polished and known as cubic zirconia. Stabilizing agents are added to Zirconium oxide to form cubic zirconia. Like diamonds, cubic zirconia is clear and colorless, with a good degree of hardness (with a Mohs score of 8-8.5).

One of the reasons these synthetic stones have become famed as substitutes for diamonds is that their shapes are similar to various diamond cuts, like oval cut or fashion cut. The gem was originally intended—like its parent Zirconium oxide—for industrial purposes. But when folks recognized these stunning similarities to diamonds, they began producing cubic zirconia stones for use in rings and necklaces.

The process for doing so was perfected in the 1970s, and brands like Swarovski started taking advantage. By the mid-80s, more than 50 million carats of cubic zirconia were being sold for fashion jewelry!

What is Cubic Zirconia: Differences Between Diamonds and Cubic Zirconia

Quick Guide—How to Tell Diamonds from Cubic Zirconia

Looking at both stones under natural light, diamonds show a strong white light (the diamond's “fire" or "brilliance") whereas cubic zirconia gives off much more colored lights (the "rainbow effect"), as cubic zirconia has a lower refractive index and higher dispersion rate than diamonds. These will be explained in greater detail below.

This is your quick way to tell which one you are working with, except for the price tag of course, wink wink.

But we’ll now go in some detail, into the differences between diamonds and cubic zirconia, so you’ll be able to make an informed decision that is best for you.

Cubic Zirconia vs. Diamond: Diamonds Color

Diamonds are classified by color. The grading scale starts at D and ends at Z. The D colored diamonds are clear. The Z colored diamonds, on the other hand, are yellow. In between are stones that are not completely icy with that amazing clear-diamond beauty, but that don’t have a clearly-defined color like yellow. The more lack of color, the more valuable the stone. Colorless diamonds are the most valuable stones in the world.

diamonds color grading

cubic zirconia, like diamonds, have their clear varieties. The reason they have functioned as affordable substitutes for diamonds is that it can look like a D-colored diamonds. While cubic zirconia can be manufactured in colors, they are more commonly colorless. That is why there’s no complex coloring system for them.

The difference is in the way the two reflect light. The diamond’s fire is more of a white light, whereas the fire of zirconia is brighter and more colorful, and that is actually what puts some people off.

round diamond on black background

Diamonds vs. Cubic Zirconia: Diamonds Clarity

Clarity is another characteristic that sets diamonds and cubic zirconia apart. It’s the place where the synthetic nature of Zirconia works as an advantage. Diamonds, as we’ve learned, are products of the depths of the Earth. Because of that, they often have flaws. There are many stones brought out of the Earth that won’t be able to be used for jewelry.

Of ones that are of gemstone quality, there are still many that have imperfections, which are called inclusions, meaning the diamond includes tracing of other elements, which take away the clarity. The lowest clarity grade of a diamond is Included, the highest Flawless.

If you are looking for great clarity, that desire may drive you toward Zirconia. Then again, flaws can make people endearing, and one might look at jewel stones the same way.

Cubic Zirconia vs. Diamond: Diamonds Dispersion

Dispersion is the way light is reflected by an object: light hits an object—a diamond, for example— and is then split into different little bits of the color spectrum. These fragments of color are then beamed into the viewer’s eye—so that’s what we see. When a diamond disperses light in this way, the light is called its “fire.”

What determines how this lovely display of light will appear is the configuration of the diamond’s facets. These are, of course, what split the light into different fragments.

Diamonds have a dispersion rate of 0.044.

This is an area in which zirconia outshines diamonds—see what we did there? cubic zirconia has a dispersion rate of 0.058-0.066. This means that this “fire” or rainbow effect is greater with cubic zirconia than with diamonds, so if that’s a priority, you have a reason other than price to go for zirconia. The difference in dispersion level between diamonds and cubic zirconia is more obvious in larger carat sizes. Thus, if you’re worried about the bling being out of control, you can go with a smaller zirconia.

Cubic Zirconia vs. Diamond: Diamonds Brilliance

So, we’ve just looked at dispersion, or light of different colors shooting from a stone, like colors of a rainbow. But there’s another big factor for gems, and that is how bright—or brilliant—they are. This refers to the depth of their sparkle or brightness, and not different colors.

The technical word for measuring brilliance is refraction or the refractive index. Diamonds have a refractive index of 2.42, higher than any gem except one called Moissanite. On the other hand, cubic zirconia is at 2.16.

This means that diamonds are brighter than cubic zirconia, but not by a large amount. You can decide how you’d like to trade brilliance for price.

Diamond vs. Cubic Zirconia: Diamonds Price

Cubic zirconia simulants are much, much cheaper than mined diamond.

For example, a flawless 1 carat round colorless diamond graded D costs around $12,000 whereas a 1 carat cubic zirconia is only worth $20.

As the carat size increases the cost difference between cubic zirconia and diamond grows even larger.

Check this diamond price calculator here.

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How Much Are Cubic Zirconia Worth?

Now that we’ve gone through the various elements of diamonds and cubic zirconia and have compared, you’re probably trying to decide if you might go for a really good simulation of a diamond or spend more money on the real thing. You’re looking for the bottom line: how valuable is cubic zirconia?

READ: Jewellery’s Value Lies in its Emotional or Sentimental Worth

In one sense you can measure the value of cubic zirconia stones (often called cz stones) in the money you don’t spend on it. Otherwise, there isn’t a lot of monetary value there, and you aren’t going to get rich selling these gems when done with them. Cubic Zirconia won’t be family heirlooms, and they don’t have sentimental value. They don’t give one the sense of prestige that diamonds do.

However, that doesn’t mean cubic zirconia re not good for your collection. For one thing, they can be a wise choice for travel. Are you on a shopping spree in New York City? Perhaps you are enjoying a mimosa by an infinity pool. With jewelry featuring cubic zirconia, you’ll have peace of mind, since you’re wearing… well… cubic zirconia. Show it off! It is just as beautiful. But in case of loss or theft, it won’t cost anywhere near as much to repair or replace.

READ: Why Smart People Buy Cubic Zirconia Engagement Rings

Cubic zirconia vs. Diamond Side By Side—The Bottom Line

So, how do these two compares against each other?

Diamonds and cubic zirconia (cz stones) look similar. However, they are very different. There are several major characteristics that set them apart. These are the origins, hardness, color, clarity, dispersion, brilliance, and value. Jewellers weigh all these factors to determine a diamond’s worth.

If you are looking for an investment that will last a lifetime, choose the diamond. Though cubic zirconia engagement rings are all the rage now, for a ring that will make your friends jealous, buy a diamond. The woman who adorns herself with diamonds lives in luxury and style.

The practical woman values the convenience of cubic zirconia. Cubic Zirconia are stunning, but for a fraction of the price. If you value sustainability, go for cubic zirconia.

Moissanite, a brilliant diamond simulant can also be an alternative to Cubic Zirconia. See how moissanite compares to cubic zirconia.


Ultimately, it is the sentimentality that we attribute our gemstone that determines its value. Only you can decide what diamonds or cubic zirconia mean to you.

So easy to misspell…

Cubic zirconia, might well be one of the easiest English word to misspell! Check out the top 25 wrong spelling found on the internet: cubiczerconia, cubics zirconia, cubuc zirconia, cubic zirconic, cubis zirconia, cubi zirconia, cubic zirc, cubic zircons, cubric zirconia, cubic zirkoner, cubix zarconia, qubic zerconia, cubit zerconia, cubix zirconium, cubix zerconia, cubit zarconia, cubit zerconium, cubin zirconia, qubic zarconia, cubic zurconian, cubic zirconian, cubic ziconian, cubic zirco, cubic zirconians, cubic zircomium….