If you find CZ written on jewelry, it’s the manufacturer’s way of letting your know that the gemstone you see on that item is made of Cubic Zirconia. CZ is the most popular diamond lookalike (or simulant) you would find if you’re shopping on a budget.
What is Cubic Zirconia (CZ)?
Since commercial production of cubic zirconia started in 1976, it has been the most popular diamond simulant. Zirconia means an oxide of the metal zirconium, while the “cubic” term refers to the arrangement of atoms in CZ. How the atoms are arranged plays a significant role in giving zirconia its diamond-like properties.
Cubic Zirconia is typically colorless, but manufacturers make it in different colors. CZ gets its brilliant diamond-esque appearance due to its high refractive index, which measures how light gets redirected as it passes through an object. Objects with higher refractive indexes, like Cubic Zirconia and diamond, will have a more significant glitter effect than air with an index of almost 1.
While many people know Cubic Zirconia more for its use in jewelry, it also plays a vital role in technology. Its hardness, extreme stability at high temperatures, and excellent thermal insulation are some of the reasons it’s used in machines such as jet engines. As a piece of trivia, the engine that powers the Airbus 380 (the world’s largest passenger jet) uses Cubic Zirconia as an essential part of its engine.
Cubic Zirconia Vs Diamond

Since Cubic Zirconia was made as a cheaper diamond alternative, there can never be any shaking off the comparisons. At first glance, it has the characteristic look and sparkle of a
diamond at a fraction of the price, but they have some key differences.
1. Price
The first and most apparent difference between CZ and diamonds is the price. Diamonds have been expensive since they’ve been used in jewelry, and they were typically reserved for the wealthy. However, the rise of the middle class has led many people to desire the luxury of the rich (or a semblance of it) at prices they can afford.
Cubic Zirconia was made to cater to that market of users who want jewelry that has the bling but cannot afford it. The price of a 1-carat diamond ranges from $2,000 to $25,000; however, you only need between $4,500 and $6,000 for a good value, high-quality stone. A Cubic Zirconia stone weighing one carat will cost $20, while a 2-carat stone will cost roughly $30.
2. Physical Attributes
Cubic Zirconia is a solid 8.5 on the Mohs scale, which is impressive but not as high as diamond which is a perfect 10. Also, CZ has a density between 5.6 and 6.0 g/cm3, compared to diamond which is around 3.5–3.53 g/cm3. This difference in density means that you can easily identify the weight difference between CZ and diamond stones of equal size.
Also, unlike cubic zirconia, diamond is a thermal conductor. It should feel cool like metal if you touch the tip of your tongue to a real diamond near room temperature. On the other hand, zirconia is a great thermal insulator; if you touch it to the tip of your tongue, it should feel much warmer, more like glass.
Finally, all diamonds have imperfections in them that are a result of the formation process. These imperfections are known as inclusions, and even synthetic diamonds have them. Cubic Zirconia is usually flawless when completed, and its clarity is similar to a D-grade diamond.
3. Appearance
That seemingly insignificant difference in the hardness of diamond and Cubic Zirconia is telling after a while. Daily wear and tear and even household dust can scratch Cubic Zirconia stones. Additionally, Cubic Zirconia absorbs oils from the skin and common products, meaning that even the most brilliant cubic zirconia will become murky and scratched after a few years.
In summary, while Cubic Zirconia might be a good-looking stone, you cannot compare it to the value and beauty of diamonds.
Is Cubic Zirconia The Best Diamond Simulant?
A diamond simulant is an object with characteristics similar to a diamond, and several have existed over the years. Diamond simulants can be either natural or synthetic. Some common examples of diamond simulants include quartz, rhinestones, strontium titanate, and moissanite.
While many diamond simulants have been trialed over the years, none has come as close to competing with Cubic Zirconia as moissanite. Moissanite is made of silicon carbonate and is extremely scarce; as a result, moissanite is grown in labs.
While moissanite has been increasing in popularity, it is a much more expensive stone than Cubic zirconia. It also has a higher hardness rating of 9.5 on the Mohs scale, second only to diamonds. Moissanite is also distinct because of its higher refractive index of 2.65, meaning it has a “fire” higher than even diamonds.
While moissanite might cost more, it’s a better diamond simulant than Cubic Zircona because it’s a more durable stone. Also, you mustn’t confuse synthetic diamond for a diamond stimulant. While the synthetic diamond is also made in a lab, it is still seen as an actual diamond. It has the same material properties as natural diamonds.
Is Cubic Zirconia A Gemstone?
When most people think of gemstones, they think of precious objects formed in rocks via a natural process over a long period. If that’s your definition, then CZ is not a gemstone as it’s mass-produced in a controlled environment over a short period. You, therefore, wouldn’t class Cubic Zirconia into the same bracket as stones like rubies, diamonds, or emeralds.
Is CZ Jewelry Real?

Image by @Cathy Cain
When people ask if Cubic Zirconia is real, they mostly think of it in relation to diamonds. However, CZ is an individual gemstone with its properties. However, some salesmen would try to convince you that what you’re buying is a diamond when it’s Cubic Zirconia.
Most jewelry items have hallmarks that briefly describe the piece, such as its producer, materials used in production, size, etc. All jewelry that uses Cubic Zirconia stones is supposed to have the CZ inscription as part of the hallmark.
Should I Buy CZ Jewelry?
Buying CZ jewelry or not is a matter of what you want. People buy Cubic Zirconia because of how affordable it is; in fact, that’s the whole point of its creation. However, if you can afford to buy authentic diamonds, Cubic Zirconia doesn’t have anything over the look and value of diamonds.
The best use of CZ jewelry is for pieces of jewelry that you intend to change soon. Another good thing about Cubic Zirconia jewelry is that since it’s very affordable, buying jewelry made of it isn’t a gamble. If you buy it and don’t like what you’ve purchased, you can easily count your losses and move on.