Skip to Content

How Can You Tell a Diamond From a Cubic Zirconia?

How Can You Tell a Diamond From a Cubic Zirconia?

We believe it is essential to explain the difference and characteristics of both diamonds and Zirconia at the very beginning so that we can further succeed through the text and teach you how to distinguish these two things yourself.

The initial and most straightforward answer we can give is: The simplest way to distinguish between these two is to remember that cubic Zirconia emits a significant rainbow of colorful light, whereas a diamond emits white light (brilliance) (excessive light dispersion).

So let’s go into detail about the answer we have provided you, as well as the key differences, features, and much more!

Diamonds And Their Characteristics

Let’s begin by defining what diamonds are!

Diamond is a rare, naturally occurring mineral made of carbon. Each carbon atom in a diamond is linked to the four carbon atoms around it by the most critical chemical bond, covalent.

This simple, homogeneous, tightly-bonded structure yields one of the most robust and versatile materials yet produced. So, diamond is the hardest known natural substance.

It also boasts chemical resistance and the most excellent thermal conductivity of any natural substance. These characteristics allow it to be employed as a cutting tool and for other jobs requiring durability.

What about diamonds value, you may wonder? A diamond’s value is influenced mainly by its four primary characteristics, or the “4 Cs”: color, clarity, cut, and carat.

Suppose a certificate accompanies a diamond with these characteristics, assigned values, and grades. In that case, evaluating the stone’s quality and comparing it to comparable stones is pretty simple.

If the gem is not certified, you can hire a gem lab, such as the GIA (Gemological Institute of America) or AGS (American Gem Society), to grade the diamond and provide a grading report.

Cubic Zirconia And How Their Manufacture Started

Cubic zirconia is a far less expensive manufactured jewel that resembles a diamond but is significantly different. A synthetic mineral formed from zirconium dioxide is cubic zirconia.

CZs can resemble diamonds, but their mineral structures are fundamentally unlike. Only a tiny fraction of the cubic zirconias used in jewelry are naturally occurring; the vast majority are manufactured in labs.

In laboratories, synthetic diamonds are also produced, but unlike cubic zirconias, they share the same carbon structure as natural diamonds.

Since the commercial manufacture of synthetic cubic zirconia started in 1976, it has remained the most significant economic and gemological rival to diamonds due to its low price, durability, and aesthetic resemblance to diamonds.

A more contemporary substance, synthetic moissanite, is its principal rival as a manufactured gemstone.

Regarding value, the idea that diamonds are expensive because they are rare and beautiful has been supplanted with the idea that they are artificially rare because of price-fixing actions by the De Beers Company, which had a monopoly on the market from the 1870s until the early 2000s.

Related Read: Moissanite Vs. Cubic Zirconia Vs. White Sapphire

How Can You Tell a Diamond From a Cubic Zirconia?

Our main question has finally arisen: Diamond vs. Cubic Zirconia!

Even though they may appear identical up close, diamond and cubic zirconia are two different gemstones.

Artificial, colorless diamonds with no brightness are cubic zirconia. Natural, beautiful jewels called diamonds are discovered deep within the ground.

Diamonds display impressive brightness and fire when they are well cut. Cubic zirconia and diamond differ substantially in value and terms of beauty and physical makeup.

Although incredibly cheap, cubic zirconias have no market value. So diamonds shouldn’t be considered investments, but they hold their value over time – typically at least 50% of what you paid.

Diamonds are precious stones that are highly sought-after and are frequently used in engagement rings and other fine jewelry. We don’t suggest cubic zirconia jewelry since it differs in beauty and quality from diamonds.

Related Read: Are Cubic Zirconia (CZ) Diamonds Fake?

So, let’s take a look at the main differences!


Appearance is the first stage in determining if cubic zirconia attempts to pass for a diamond.

The two stones may appear to be identical to the eye of a non-jeweler, but there are some little distinctions you should be aware of.

Diamond enthusiasts know that a “white” diamond might have a yellow, gray, or brown tinge, despite the misconception that a diamond should be apparent.

An M color white diamond would be somewhat yellower than an F color diamond, for example.

This is what gives the D-Z color scale its name.

Cubic zirconia is less likely to have any color, not yellow, gray, or any other.

A diamond will have natural inclusions dispersed throughout the stone, which is another distinguishing feature and proof that the stone is genuine.

Usually, a microscope is the only way to observe these inclusions.

Let’s take a look at the next one!


Even though these stones may have a similar appearance, their compositions are highly diverse.

Consider the hardness while attempting to distinguish between diamonds and cubic zirconia.

A diamond is the most burdensome stone known to man, but cubic zirconia rates far lower on the hardness scale.

Carbon is a substance that gives diamonds their hardness and sparkle.

Checking the weight is another way to see if it works. Although the physical size of a diamond and cubic zirconia can be the same, cubic zirconia weighs more because it is a little denser.


The price is the last indication that anything is wrong.

Although the cost of diamonds might vary depending on their size or other qualities, they nearly always cost more than cubic zirconia.

Our Advice: Ask to view the certifications if the price of a piece of diamond jewelry appears excessive for what you are getting to guarantee that it is a real diamond and not a synthetic stone or fake diamond being sold as the real thing.

Although the cost is sometimes the main distinction between diamonds and cubic zirconia, you should still exercise caution.

A little diamond, for instance, can be less expensive than a substantial cubic zirconia stone. Of course, using a trustworthy dealer is the best approach to steer clear of any problems.

Building a relationship with a reputable jeweler can give you more confidence in the diamonds you add to your collection!

The Best Techniques To Separate A Cubic Zirconia From Diamonds

1. Look for Cubic Zirconia at a Lesser Cost

Cubic zirconia is substantially less expensive to cut and make since it is created in a lab.

While a 1-carat diamond may sell for $20,000, a 1-carat chunk of cubic zirconia might cost approximately $20. A far lower price often denotes cubic zirconia rather than a diamond in a piece of jewelry.

While colored cubic zirconia will cost about the same as colorless cubic zirconia, colorful diamonds are sometimes significantly more costly than colorless ones.

2. Look for Cubic Zirconia in Low-cost Jewelry Settings

Since cubic zirconia is less expensive than a diamond, it is typically used in slightly less expensive jewelry.

There is a strong likelihood that your jewelry contains cubic zirconia if the settings are made of gold-filled or gold plated rather than solid gold.

Verify any marks on the back or inside of your item. If they are solid gold and feature the marks 10K, 14K, or 18K, you most likely have a genuine diamond.

Cubic zirconia is used when jewelry has the C.Z. designation. This can’t tell you with certainty if your piece is a diamond or not since diamonds are occasionally put in jewelry that is not made of solid gold.

3. Expose Your Jewelry to The Sun to Detect Cubic Zirconia by a Dazzling Flash

Diamonds are excellent at playing with light, but cubic zirconia intensifies the rainbow appearance when exposed to the sun.

Take your jewelry outside to observe how it responds to light. It is likely cubic zirconia if it sparkles brightly and in various hues. Smaller cubic zirconia fragments could not shine as brightly.

Related Read: How Should A Diamond Look In Sunlight?

4. Check Your Stone to See Whether the Fog Swiftly Dissipates to Reveal a Diamond

To make fog, blow hot air onto your piece of jewelry. Your item is probably a diamond if the fog immediately dissipates because diamonds have limited thermal conductivity and can’t retain heat for very long.

Your item is most likely cubic zirconia if the fog lasts 30 seconds or more since it has a solid thermal conductivity and may retain heat for a long time.

If you have a diamond tester that gauges heat conductivity, you may also utilize it. Typically, cubic zirconia has a higher heat conductivity.

5. To Determine a Diamond, Check if Your Item Sinks

Fill a glass with room temperature water until it is about 3/4 full. Into the glass, place your loose stone.

The stone is probably cubic zirconia if it floats. Since diamonds are denser than water, anything that sinks is almost certainly a diamond.

To ensure that you don’t lose your stone after the test, use tweezers to remove it from the water.

If your stone is placed in a piece of jewelry, this test won’t function.

6. Use Opaqueness as a Diamond Identification Test

Use a permanent marker to draw a black line on a sheet of white paper.

Cross the line with your piece.

It is probably cubic zirconia if you can see through your item to the line beneath. It is most likely a genuine diamond if you can’t see the line.

Once again, if your item is already set in jewelry, you can’t do this test.

7. Keep an Eye out for Wear-and-Tear Signs Like Scratches that Might Be Cubic Zirconia

Diamonds have a very long lifespan and are not easily scratched.

After a few years of usage, if your item is damaged or foggy, it most likely contains cubic zirconia. Also, It is most likely cubic zirconia if it has chips or gouges.

How Can You Tell If Cubic Zirconia And Diamonds Are Real?

Although cubic zirconia is a genuine gemstone, it is not a natural diamond.

A few other stones may be used to simulate diamonds, but cubic zirconia is by far the most popular and realistic option.

There are a few techniques to determine whether a diamond is genuine.

The only surefire way to tell is to take it to a jeweler or gemologist who can test it using certified machinery. However, there are a few at-home techniques you may apply to get a good approximation.

Diamonds won’t wear down or scratch since they are tougher than virtually any other material; they will damage other surfaces.

If you have a microscope or magnifying lens, examine the stone’s edges where the facets meet; if they appear mushy, worn down, or rubbed, it is most likely not a diamond.

The edges of a diamond’s facet will often appear extremely exact and sharp.

Look at the hue of the light as it passes through and through the stone’s surface. The bottom of a diamond will reflect every hue of the rainbow when turned upside down, but the bottom of a CZ would often only reflect orange and blue flashes.

This is because the refractive indices of diamonds and cubic zirconia are dissimilar.

Since cubic zirconia is more insulating than diamonds, which are rather good at thermal transmission compared to other stones, cubic zirconia will warm up in your palm more slowly than diamonds.

Final Thoughts

We started today’s topic with a question that reads: How can you tell a diamond from a cubic zirconia?

And our first task was to prepare for you the most straightforward answer to it, which is:

Observing the gems in natural light makes telling cubic zirconia from a diamond the most straightforward task. This is because a diamond emits white light (brilliance), but cubic zirconia emits a broad spectrum of colored light (excessive light dispersion).

However, as we mentioned at the very beginning, we felt that this answer was not reasonably sufficient. That is why, through this article, we tried to begin with more information such as, what diamonds are, what cubic zirconia is, and what their characteristics are so that you can better understand their differences.

We hope that, with our help, you’ve had the opportunity to enjoy, in addition to learning new things and gathering information!