If you've ever shopped for jewelry in stores or online, you've probably seen lab grown diamonds and cubic zirconia (CZ) mentioned in the same breath. They both sparkle beautifully, are both synthetic and to the untrained eye, they might look similar. But here is the reality, lab grown diamonds are real diamond. Cubic zirconia is a diamond simulant, created to look like a diamond.
In this guide, we’ll break down exactly what makes them different—how they’re made, how they perform over time, and why a lab grown diamond is a far more valuable choice if you want lasting brilliance and heirloom quality.
What Is a Lab Grown Diamond?
A lab grown diamond is a real diamond that has been created in a controlled laboratory environment, instead of mined from the earth. Lab grown diamonds are made from pure carbon, and effectively have the same chemical, physical and optical properties of a natural diamond because they were crystallized in the same manner.
Lab grown diamonds are formed using two advanced methods:
- HPHT (High Pressure, High Temperature): This method replicates the extreme heat and pressure that occurs deep within the earth to encourage carbon atoms to bind together and grow into a diamond crystal.
- CVD (Chemical Vapor Deposition): A modern process where a thin diamond "seed" will grow layer by layer in a chamber filled with carbon-rich gas; thereby, producing high-quality and stunning diamonds.
Because lab grown diamonds have the same hardness, brilliance and durability as mined diamonds, lab grown diamonds are also certified, graded and loved just like their earth-mined counterparts, with the added benefit of being a more ethical and affordable option.
What Is Cubic Zirconia (CZ)?
Cubic zirconia (CZ) is a popular substitute for diamonds, but it's key to recognize that it is not a diamond. CZ is an entirely synthetic gemstone made of zirconium dioxide and created in a lab to imitate the aesthetic of a real diamond.
While CZ may be very sparkly when new, it does not have the same physical or chemical properties as a diamond. CZ is much softer, with a hardness of about 8-8.5 on the Mohs hardness scale (diamonds are 10), and can scratch or cloud over time, losing their bling factor.
Because CZ is cheap and mass-produced, it is commonly used for fashion or costume jewelry. CZs can be fun and inexpensive pieces for wearing casually, but they do not have the length of durability or long-term value of a lab grown diamond.
Are Lab Grown Diamonds the Same as Cubic Zirconia?
No, lab grown diamonds and cubic zirconia are not the same thing.
A lab grown diamond is a real diamond! It is made of pure carbon and is exactly the same as a mined diamond in every way; chemically, physically, and optically. It has the same unbelievable hardness (10 on the Mohs scale), same brilliant light performance, and durability.
Cubic zirconia is a diamond simulant. It is made to look like a diamond but is made of zirconium dioxide, a totally different material. CZ can shine if the light is right, but it does not have the same fire, brilliance or lasting value of a real diamond.
Simply put: if you want a diamond that lasts a lifetime and holds real value, lab grown is the clear winner.
Lab Grown Diamonds vs. Cubic Zirconia: What’s the Difference?
Both lab grown diamonds and cubic zirconia will sparkle upon first look, but when you dive a little deeper, you'll find that their quality, durability, and value are vastly different. Here’s how they compare:
Hardness and Durability
For hardness, lab grown diamonds rate the same as mined diamonds--10 on Mohs hardness scale--making them resistant to scratches, chipping and everyday wear and tear. This is an important factor when choosing for every day jewelry like engagement rings or wedding bands. Cubic Zirconia has a hardness rating of 8-8.5, making it easily scratched and cloudy or dull over time.
Brilliance and Sparkle
Lab grown diamonds have superior brilliance, fire, and scintillation thanks to their precise faceting and natural diamond crystal structure. So because of their sparkle, lab grown diamonds shine beautifully in solitaire diamond necklaces and stud earrings, where light performance is the star of the show. CZ may have a flashy sparkle when new, but it can appear glassy and overly rainbow-like, making it fairly easy to distinguish from a real diamond in proper lighting.
Color and Clarity
Lab grown diamonds are graded like all mined diamonds, from colorless D-grade, to warmer tones, with most being near-flawless facilitates thanks to advanced growing technology. Cubic zirconia is typically manufactured to look flawless, but its excess of clarity can appear artificial to the trained eye.
Price and Value
Cubic zirconia is incredibly affordable. Plus, it usually costs just a few dollars a carat. However, there is no resale value for cubic zirconia. Lab grown diamonds, which are significantly less expensive than mined diamonds, are also real diamonds with their own intrinsic value, which makes them suitable for investment pieces and heirlooms.
Long-Term Wear and Longevity
Lab grown diamonds are made to last a lifetime and are not only scratch resistant but retain their brilliance for generations to come. CZ is suitable for short-term or fashion wear because it tends to scratch, become cloudy or lose its luster with daily wear.
Can You Tell the Difference Between a Lab Diamond and CZ?
Yes, in most situations, you can tell the difference between a lab grown diamond and cubic zirconia, especially when you know what to look for.
To the naked eye:
- Lab grown diamonds exhibit a crisp, sharp sparkle that has a combination of bright white light (brilliance) and flashes of colors (fire).
- CZ is often overly rainbow-like in its sparkle and can attain a slight glassy, dull look, especially after it has been worn for awhile.
By weight and feel:
Cubic zirconia is significantly denser than a diamond so if you hold a CZ and a lab grown diamond of the same carat size, the CZ will feel decidedly heavier in your hand. The difference is slight but you will be able to feel it when comparing two stones, especially large carat sizes.
The fog test:
A quick test that you can do at home is to breathe on the stone as you would a mirror to fog it up. Diamonds (lab grown and mined) are great heat conductors which means the condensation from your breath will evaporate almost instantly, within a second or two. On the other hand, Cubic zirconia don’t conduct heat well, will still stay fogged for a few seconds longer which would be a quick and easy way to tell the two apart.
Professional verification:
While these at-home methods can help, a jeweler can easily confirm the difference with a diamond tester or magnification. At Lucenjuri, all our lab grown diamonds are IGI or GIA certified, giving you full confidence in their authenticity.
Shop Certified Lab Grown Diamonds at Lucenjuri
At Lucenjuri, we believe you deserve jewelry that’s as authentic as your love story. That’s why every diamond we offer is lab grown, ethically sourced, and certified—so you can shop with complete confidence.
Whether you’re searching for a sparkling engagement ring, a meaningful anniversary gift, or a timeless everyday piece, our collection combines exceptional craftsmanship with modern sustainability. And unlike cubic zirconia, your Lucenjuri diamond will shine brilliantly for a lifetime.
EXPLORE LUCENJURI LAB GROWN DIAMONDS NOW
FAQs
Is a lab diamond a cubic zirconia?
No. A lab grown diamond is not a cubic zirconia, a lab grown diamond is a real diamond made of pure crystallized carbon, just like mining diamonds. Cubic zirconia is a diamond simulant made of zirconium dioxide to look like a diamond but does not possess a diamond's natural sparkle, hardness, or long-lasting durability.
Are lab grown diamonds better than cubic zirconia?
Lab grown diamonds are real gemstones with exceptional hardness, brilliance, and lasting value. Cubic zirconia is an affordable alternative but tends to scratch, cloud, and lose its sparkle over time. If you're trying to find a diamond that will last generations, lab grown is the way to go.
How can I tell if it’s cubic zirconia or a real diamond?
You can look for key differences:
- Sparkle: Diamonds have sharp white brilliance and colorful fire, while cubic zirconia often looks glassy or overly rainbow-like.
- Fog Test: Diamonds disperse heat quickly, so fog disappears almost instantly. CZ stays fogged longer.
- Wear Over Time: Diamonds remain brilliant for a lifetime, but CZ scratches and clouds easily.
Can a jeweler tell the difference?
Absolutely. Jewelers have diamond testers and magnification they can use to quickly identify a lab grown diamond from CZ. A certified lab diamond will also come with IGI or GIA grading, something that CZ does not have.
Are lab grown diamonds used for fine jewelry?
Absolutely. While cubic zirconia is better suited for casual or fashion jewelry, lab grown diamonds are perfect for fine jewelry pieces like halo engagement rings, anniversary bands, and delicate pendant necklaces, where long-lasting sparkle and heirloom-level durability truly matter.
