This guide provides a clear, factual comparison to help you make a smart jewelry investment.
Quick Comparison
- Identity: Lab Diamond is a real diamond. Cubic Zirconia (CZ) is a simulant (fake).
- Durability: Lab Diamond is a 10/10 on the Mohs scale (lasts forever). CZ is an 8.5 (scratches and clouds over time).
- Value: A 1-carat Lab Diamond costs ~$1,500 and holds value. A 1-carat CZ costs ~$20 and has zero resale value.
- Best For: Lab Diamonds are for permanent jewelry (like engagement rings). CZ is for temporary fashion jewelry.
Shoppers evaluating jewelry face a confusing choice between two stones that appear nearly identical. Lab grown diamonds and cubic zirconia (CZ) both offer a clear, brilliant alternative to mined diamonds, but they are fundamentally different materials.
One is chemically identical to a natural diamond; the other is a simulation. This distinction impacts everything from their sparkle to their long-term value. This guide provides a clear, factual comparison of the difference between lab grown diamonds and cubic zirconia to help you make a serious, smart jewelry investment.
What Are Lab Grown Diamonds?
Lab grown diamonds, also known as man-made or cultured diamonds, are the result of a technological process that replicates the natural diamond-growing environment.
How They’re Made
There are two primary methods used to create lab diamonds:
- High Pressure, High Temperature (HPHT): This process mimics the intense pressure and heat of the earth’s mantle. A small diamond "seed" is placed in a cell with pure carbon and subjected to extreme temperatures and pressure, causing the carbon to crystallize around the seed.
- Chemical Vapor Deposition (CVD): This method uses a hydrocarbon gas mixture in a vacuum chamber. A diamond seed is heated, and the gases are broken down with microwaves or lasers. The carbon atoms attach to the seed, growing the diamond layer by layer.
Are They Real Diamonds?
Yes. This is the most important fact to know. A lab grown diamond is chemically, physically, and optically identical to a mined diamond. It is pure carbon crystallized in a cubic structure. It possesses the same brilliance, fire, and scintillation. Lab created diamonds vs fake diamonds is a false comparison; lab diamonds are real diamonds.
What Is Cubic Zirconia?
Cubic zirconia is a diamond simulant. It is engineered to look like a diamond, but it shares none of a diamond’s chemical or physical properties.
Origins & Composition
Cubic zirconia is the cubic crystalline form of zirconium dioxide. While a natural form was discovered in the 1930s, the material used in jewelry today is entirely synthetic. Its mass production began in the 1970s as an affordable alternative to diamonds.
Why It’s So Cheap
CZ is inexpensive because it is simple and fast to mass-produce. It is not carbon. It is not a gemstone. It is a synthetic material created in a lab, and its cost reflects its status as a diamond simulant rather than a diamond itself.
Expert View: How to Tell the Difference
While lab diamonds and simulants like CZ or Moissanite can look similar, a trained eye—and a few simple tests—can reveal their true identity. Watch this quick visual guide to see the differences in action.
"...when I flip this Stone [Cubic Zirconia] over and put it up against lines or letters on a piece of paper you can easily see those letters and lines through the stone... when I look through the diamond upside down you can't really see the letters through the diamond..."
Click to view full video transcript
0:00 look at these four diamonds or actually 0:02 I should say gemstones because they 0:04 aren't all diamonds one is a natural 0:06 Earth M Diamond one is an artificial lab 0:09 Diamond one is a cubic zerconia Stone 0:12 and one is a moite stone in this video 0:14 I'm going to show you how to tell which 0:17 is which I'm Rick buck and I've been a 0:19 diamond consultant for over 6 years 0:21 there are a few ways to tell what Stones 0:24 we have here and let's start by locating 0:25 the moist KN because that is the easiest 0:28 in my opinion to detect of all the fake 0:30 diamonds there's one dead giveaway for 0:33 most moist and nights today and it's 0:34 found by doing what I call the fog test 0:37 I will take these four stones and fog 0:39 them up with my breath as you would on a 0:41 car window as a child and you will spot 0:44 the moist night very easily the moist 0:47 Knight Will fog faster easier and stay 0:50 fogged longer so you can see the second 0:53 one from the left stays fog much longer 0:56 than the others the others barely fog if 0:59 at all just to show you how well this 1:01 technique works these are four different 1:03 Stones the three on the right are moist 1:06 nights and the one on the left is a 1:07 diamond you can see what happens when I 1:10 fog them with my breath all three moist 1:13 knes fog up the diamond doesn't so back 1:16 to the original four that we were 1:18 analyzing we will take the suspected 1:20 moist Knight out and look at it some 1:21 more here we are measuring its diameter 1:24 with a bowly gauge you can see it is 1:26 about 6.5 mm in diameter if it were a a 1:30 diamond a 6.5 diameter diamond would be 1:33 about 1 karat which you take and divide 1:36 it by five and it gives you the weight 1:38 in G which is2 G you can see that it 1:42 matches up pretty close so you might 1:44 think maybe it is a diamond however 1:47 you're going to have to follow me for a 1:48 second because you can mimic the 1:50 diameter to weight ratio of a diamond 1:53 with a moist KN but the rest of how the 1:55 diamond is cut will look slightly 1:58 different to achieve that so to analyze 2:00 the cut we look through what we call an 2:03 AET scope the stone on the left is a 2:05 moonite and the stone on the right is a 2:07 diamond for reference the inner blue 2:09 arrows on the left moist Knight are 2:11 Stumpy than the diamond on the right so 2:14 I can tell I am definitely correct about 2:17 this being a moist knite now I showed 2:19 you those Arrows with the AET scope but 2:21 you can definitely tell in daylight as 2:24 well if you know what you're looking for 2:26 once again the stone on the left is 2:28 moist andite and the Stone on the right 2:31 is a diamond you can see the Stumpy 2:33 arrows on the inner circle of the moist 2:35 Knight and the longer ones on the 2:37 diamond and this is in just pure 2:39 daylight you see because moist Knight is 2:41 lighter and the diameter is the same to 2:43 get it to weigh the same as a carrot it 2:45 had to make it longer and so the 2:47 underlying Peak is a little bit deeper 2:49 to increase the weight but the problem 2:51 is once the depth increases the inner 2:54 arrows look much Stumpy too so match all 2:57 of those up with the AET scope and those 2:59 blue spikes or arrows we just looked at 3:02 as you can see do not match up with what 3:04 you would expect a 6.5 1 karat diamond 3:08 to look like you see you can't have it 3:10 all the diameter carrot weight depth cut 3:13 design and fogginess can't all three 3:16 match up now there is one last way to 3:19 tell it is a moist night just look for 3:21 an inscription most certified diamonds 3:24 today will have an inscription that you 3:26 can see under magnification that will 3:28 match up with a lab certificate and 3:30 report so here's that diamond that we 3:33 were just looking at and its 3:35 corresponding lab report once you have 3:37 this number you can look up that lab 3:39 report with its inscription number 3:41 online now look for the inscription on 3:43 the mois night some moist nights like 3:46 this one have an inscription too some 3:48 don't but this moist KN has the 3:50 inscription done sloppily on the girdle 3:52 as well with a lab called gr I don't 3:56 know much about this gr but it has a 3:58 website where you can look up your moist 4:01 knite as well so it definitely is a 4:04 moist knite and I am definitely sure 4:06 this is moist knite before we move on to 4:08 the others let me show you a terrible 4:10 way to test for diamonds and moist 4:12 nightes here's a $100 diamond tester 4:14 from Amazon the tester is very 4:17 inconsistent it says the moist knite is 4:19 a diamond sometimes and it says that 4:21 more often than it will tell you that it 4:23 is a moite again here are three moist 4:27 knes and sometimes this D diamond tester 4:30 says that they are diamonds and 4:32 sometimes it says that they aren't 4:33 lastly a cheap $20 diamond tester says 4:36 this moonite is actually a diamond so 4:38 they are inconsistent and if they're 4:40 inconsistent it means they are not worth 4:42 it at all now let's go back and look at 4:45 all four stones again since I know one 4:48 is cubic zerconia let's look at all of 4:50 them under normal indoor lights I can 4:52 pretty much tell this Stone on the far 4:55 left is a cubic zerconia it doesn't have 4:57 the distinguishable spikes that we saw 4:59 on the moite or diamonds earlier in case 5:02 you already forgot remember those blue 5:04 arrows we could see on the AET scope now 5:06 here is the diamond on the right and the 5:09 cubic zirconia on the left under the AET 5:11 scope the blue arrows look more like the 5:13 rest of the facet triangles of different 5:16 colors on the cubic zerconia now ready 5:19 for the dead giveaway that this is a 5:20 cubic zerconia when I flip this Stone 5:23 over and put it up against lines or 5:25 letters on a piece of paper you can 5:27 easily see those letters and lines 5:29 through through the stone when I look 5:30 through the diamond upside down you 5:33 can't really see the letters through the 5:35 diamond because it's taking not the 5:36 light from underneath it but the light 5:38 that's coming from above it and 5:39 reflecting it back at your eye the 5:41 moonite is much like the diamond in that 5:44 aspect too to make it even more obvious 5:47 when the CU zerconia is faed down under 5:49 the acid scope you can see right through 5:52 it and that's because once again cubic 5:54 zeronas don't really refract light they 5:56 just shine light through it the cubic 5:59 zerconia is on the left and the diamond 6:01 is on the right face down not that we 6:03 need more proof but here the diameter of 6:06 the cubic zirconia is 6.5 mm which means 6:09 it should be around 1 karat if it were a 6:11 natural diamond but this is almost 6:13 around 2 karat so it is just more and 6:17 more obvious that this is a cubic 6:18 zirconia now those diamond testers from 6:21 earlier can actually detect that this is 6:23 not a diamond and likely a cubic 6:25 zerconia even the cheap testers give 6:28 similar results before I get to the best 6:30 part make sure you watch all my videos 6:32 on how to plan the perfect proposal I 6:35 have thousands of ideas and tips on 6:37 things like how to plan and photograph 6:39 The Proposal so you have great memories 6:42 also if you want more money to spend on 6:44 the engagement I show you how to save 6:47 hundreds to thousands on the ring and 6:49 she will be impressed Jewelers know that 6:52 this is a one-time purchase you know 6:54 nothing about so take all my tips so you 6:57 don't get ripped off and use the links 6:59 below the this video because those are 7:00 the best places to buy rings and also 7:03 help to save money on those rings so you 7:05 can apply that to an amazing engagement 7:08 okay now we have the two diamonds to the 7:10 right I probably should have started 7:12 with testing for Earth diamonds because 7:14 a lot of times it is the easiest to 7:16 detect here I take focused longwave UV 7:19 light from a single beam and I shine it 7:21 on the four stones and you see the third 7:24 one from the left faintly starts to Glow 7:27 while the others don't at all this is 7:29 called fluoresence only Earth created 7:31 diamonds will do this with longwave UV 7:34 light in this manner so this is 7:37 definitely the Earth mine diamond why 7:40 almost all Earth created diamonds have 7:42 Trace fluorescent molecules in their 7:45 Elemental Matrix lab created diamonds 7:47 will not have fluoresence to longwave 7:50 fluoresence some will have a different 7:52 type of a glow to longwave fluorescence 7:54 but it will look different than this 7:56 uniform glowing here I added another 7:58 diamond with strong fluoresence on the 8:00 far right to show you strong fluoresence 8:03 now it is true that there are some Earth 8:05 created diamonds that don't have 8:07 fluoresence in them at all but most have 8:10 at least a little bit for example in our 8:12 original Four Diamonds the earth created 8:14 diamond I have detected shouldn't have 8:17 any fluoresence according to the Gia 8:20 fluoresence grade as seen in its 8:22 corresponding lab report but with my 8:24 intense focused UV light you can see it 8:27 very much does have fluorescence not all 8:29 UV lights will work as I've been saying 8:31 nail salon UV lights aren't good for 8:33 this test because they will only reveal 8:35 a strong fluorescence you see here the 8:38 third from the left is the strong 8:40 fluorescence and the fourth from the 8:41 left is our same Diamond that supposedly 8:45 had no fluoresence it looks like just 8:46 all the other stones that aren't 8:48 diamonds but we know it does have 8:51 fluoresence with good UV light in the 8:53 right settings cheap UV lights won't 8:56 normally reveal the mildly fluorescent 8:58 diamonds as my liked it now the actual 9:01 best way to see this is a real diamond 9:04 as we said earlier is to look up the 9:06 inscription under magnification and then 9:08 look up the lab report online not all 9:11 diamonds have this inscription but most 9:13 do today once you get the certificate 9:16 just match the characteristics to the 9:18 diamond that you have on the 9:20 corresponding report you can see this 9:22 diamond is about 6.41 to 6.44 mm in 9:26 diameter depending on where you measure 9:28 the diameter and the weight should be 9:31 1.01 karat or 2.02 gam this is pretty 9:36 much matching up so we can just be 9:38 pretty much sure that this is the earth 9:40 created diamond from that group and we 9:42 can tell that from the lab report and 9:45 its corresponding inscription number the 9:48 best way to test for lab created 9:49 diamonds on your own is to just use the 9:52 process of elimination the diamond on 9:54 the right here doesn't fog it doesn't 9:56 have fluoresence like Earth created 9:58 diamond is lacking Anatomy like cubic 10:00 zonia and it has all the other 10:03 properties of a diamond with weights 10:06 that match how a diamond should weigh so 10:08 this is likely the lab Diamond there are 10:11 more sophisticated ways to tell this is 10:13 a lab created diamond that a 10:14 professional must do they can test for 10:16 lack of nitrogen with light spectroscopy 10:19 as you can see here this peak 10:21 highlighted on this report indicates 10:23 from the spectroscopy that the diamond 10:25 tested has nitrogen in it and it's 10:27 highly probable this Diamond that was 10:30 tested on this report was a real diamond 10:32 I don't have this expensive equipment to 10:34 test our diamonds but some professionals 10:36 will professionals can also look at the 10:38 microscopic flaws that the diamond has 10:41 and can tell if the flaws are typical of 10:43 an earth created diamond or a lab 10:45 created diamond but once again the best 10:48 way to tell is to look at the lab 10:50 certificate all reputable Diamond stores 10:52 sell certified diamonds that come with a 10:54 lab report or certificate you should 10:57 just watch my video on reading lab 10:58 certificate gets to know everything 11:00 about them it is the best way to avoid 11:02 getting ripped off on buying a diamond 11:05 and once again this report coincides 11:07 with the inscription on the girdle of 11:09 the diamond in fact most lab grow 11:11 diamonds are inscribed as such on the 11:13 diamond like ours it will just say lab 11:16 grown microscopically on the girdle of 11:19 the diamond it doesn't get much easier 11:21 than that and that means the 11:22 professionals already did all this work 11:24 for you you can see the difference under 11:26 microscopes with a little training for a 11:28 lot of low Clarity grade lab grown 11:31 diamonds but it's too long of an 11:34 explanation for this video and you have 11:36 to know the different characteristics 11:38 depending on how the lab Diamond was 11:40 created but that is the gist of it here 11:43 is the difference in Sparkle of the Four 11:45 Diamonds this isn't an official test 11:47 there are different types of Sparkle but 11:50 in some ways diamonds sparkle more and 11:53 in some ways moist knes can sparkle more 11:55 to me cubic zirconia and moist knes do 11:58 just look d doer than the natural 12:01 diamond I hear a lot of people say you 12:03 can't really tell the difference between 12:05 all of these but you really can and some 12:07 of them are very quite obvious the way 12:10 you can tell moving on on my channel I 12:13 have tons of proposal tips and idea 12:15 videos from how to plan photograph and 12:18 deliver the perfect proposal that she is 12:21 going to love also watch one of my many 12:23 how to shop for engagement rings and 12:25 Diamond videos or mark my words they 12:28 know how to to rip you off the best 12:30 places to buy diamonds are in the 12:32 description below to save hundreds to 12:34 thousands on engagement rings and they 12:36 are the best and most reputable places 12:39 to buy diamond engagement rings like 12:41 subscribe and watch another one now
Key Differences You Need to Know
When comparing lab grown diamonds vs cubic zirconia, the differences are not subtle; they are absolute.
Brilliance & Appearance
A common question is, which looks more real, lab diamond or CZ?
- Lab Grown Diamond: A lab diamond reflects light with exceptional brilliance (white light), fire (colored light), and scintillation (sparkle). Because it is a real diamond, it does look like a real diamond—because it is one.
- Cubic Zirconia: A CZ stone is known for its intense "rainbow effect." This excessive fire is a common giveaway that it is not a diamond. CZ has a lower refractive index and reflects less white light. To a trained eye, it can appear glassy or artificial.
Hardness & Durability
This is a critical distinction for any piece of jewelry intended for long-term wear.
- Lab Grown Diamond: A diamond is the hardest known mineral, ranking a 10 on the Mohs scale of hardness. This exceptional lab grown diamond hardness means it is virtually scratch-proof against any material other than another diamond.
- Cubic Zirconia: CZ ranks between 8 and 8.5 on the Mohs scale. While hard, it is significantly less durable than a diamond. Its cubic zirconia scratch resistance is low; household dust and surfaces can easily cause fine scratches on its facets.
This cubic zirconia vs diamond durability gap is one of the most significant factors in jewelry selection.
Cost Comparison
The price difference lab diamond vs cubic zirconia is vast.
- Lab Grown Diamond: A lab diamond offers significant savings compared to a mined diamond of identical quality, often 50-70% less. A high-quality 1-carat lab diamond might cost between $1,000 and $2,000.
- Cubic Zirconia: CZ is exceptionally cheap. A 1-carat CZ stone typically costs between $10 and $20.
Why are lab grown diamonds expensive if they are made in a lab? The process requires sophisticated, energy-intensive technology and skilled technicians over several weeks or months. CZ, by contrast, can be produced quickly and cheaply in large batches.
Longevity & Resale Value
- Lab Grown Diamond: A lab diamond will last forever, just like a mined diamond. It will not cloud, scratch, or discolor. While the lab diamond resale value is still establishing itself in the market, it does retain value.
- Cubic Zirconia: The cubic zirconia lifespan is short. Because it is porous and soft (relative to a diamond), it absorbs oils from the skin, soap, and lotions. Over time, CZ will inevitably become cloudy, dull, and scratched. It has zero resale value.
“Lab diamonds are identical to mined diamonds. You’d need spectroscopy to tell them apart, which is science-speak for ‘even your jeweler’s loupe is basically a fancy magnifying glass that knows nothing.’”
“CZ, on the other hand, is an entirely different material. It's to diamond what instant coffee is to espresso: technically the same idea, but with fewer bragging rights and a suspicious shine that says, ‘I was on sale.’”
What About Moissanite?
A third stone, Moissanite, is often part of this conversation. Like CZ, it is a diamond simulant, but it is made of silicon carbide and has properties closer to a diamond, including a hardness of 9.25.
While it also has a "rainbow effect," many find it a more convincing and durable simulant than CZ.
Which Is Better for Jewelry?
The choice between lab diamonds vs CZ depends entirely on the buyer's intent.
Engagement Rings
Let’s be clear: cubic zirconia is not a suitable stone for an engagement ring.
An engagement ring is a "forever" purchase, a symbol of permanence. The best stone for engagement rings is one that can withstand daily wear for decades without losing its beauty. A CZ will scratch and cloud, often within just a few years, betraying its temporary nature. A lab grown diamond offers the same permanence and beauty as a mined diamond at an accessible price.
Everyday Wear
For everyday jewelry like earrings or pendants, lab grown diamonds are the superior choice due to their durability. A CZ stone may be acceptable for fashion or travel jewelry that is worn infrequently and expected to be replaced. For permanent pieces, you'll also want to protect them in a quality jewelry safe.
Ethical & Environmental Factors
Both stones are considered ethical alternatives to mined diamonds, as they avoid the conflicts and human rights issues associated with "blood diamonds."
In a comparison of lab diamonds vs CZ for sustainability, the issue is complex. Lab diamonds require significant energy to produce, though many growers are moving toward carbon-neutral certification. Cubic zirconia requires less energy but is essentially a disposable, mass-market product.
A lab grown diamond is the sustainable choice for a high-quality, permanent piece of fine jewelry.
Visual Comparison: Lab Diamond vs. Cubic Zirconia
| Feature | Lab Grown Diamond | Cubic Zirconia (CZ) |
|---|---|---|
| Material | 100% Crystallized Carbon | Synthetic Zirconium Dioxide |
| Status | Real Diamond | Diamond Simulant |
| Hardness (Mohs) | 10 (Extreme durability) | 8.0 - 8.5 (Scratches easily) |
| Brilliance | High (White light) | Moderate (Glassy) |
| Fire (Sparkle) | Balanced sparkle | Extreme "rainbow effect" |
| Longevity | Permanent; will never cloud | Clouds and scratches over time |
| Cost (1-Carat) | $1,000 - $2,000 | $10 - $20 |
| Resale Value | Yes (Retains partial value) | None |
Buy Smart: A Quick Checklist
| Question | Lab Diamond | Cubic Zirconia |
|---|---|---|
| Will it last 10+ years? | ✅ | ❌ |
| Will it pass a diamond tester? | ✅ | ❌ |
| Can it be insured as a diamond? | ✅ | ❌ |
📥 Download the Smart Jewelry Buyer's Guide
Get your printable checklist for confident jewelry shopping.
Download PDFWhich One Should You Choose?
Here is the bottom line: a lab grown diamond and a cubic zirconia are not in the same category.
A lab grown diamond is an investment in permanent, fine jewelry. It is a real diamond that offers identical beauty and durability to its mined counterpart at a lower, more ethical price point.
Cubic zirconia is a cheap, temporary accessory. It is an imitation, and is cubic zirconia better than lab diamonds is not the right question. The correct question is one of budget and purpose.
If you are serious about smart jewelry buying for a significant piece like an engagement ring, a lab grown diamond is the clear and logical choice.
FAQs
Is cubic zirconia fake? Yes. In the context of fake diamond vs real diamond, cubic zirconia is a "fake" or simulated diamond. It is not a real diamond.
Can lab diamonds pass a diamond tester? Yes. Lab grown diamonds are 100% real carbon diamonds and will pass all standard diamond testers that measure thermal or electrical conductivity.
Will CZ scratch or cloud over time? Yes. Cubic zirconia is porous and relatively soft. It will absorb oils and chemicals, causing it to become cloudy. Its facets will scratch with everyday wear, permanently dulling its sparkle.
