Do Lab Diamonds Test as Real Diamonds?
Do Lab Diamonds Test as Real Diamonds? What Jewelers Actually Check
One of the most common questions about lab-grown diamonds is whether they pass the same tests as natural diamonds. If you're worried about buying a lab diamond and having it questioned or rejected by a jeweler, this guide will put your mind at ease. Let's look at exactly what jewelers test for and how lab diamonds perform.
The Simple Answer: Yes, They Test as Real Diamonds
Lab-grown diamonds pass every standard test for diamonds because they are real diamonds. They have the same chemical composition, crystal structure, and physical properties as natural diamonds. When a jeweler uses standard diamond testing equipment, a lab diamond will register as a genuine diamond every single time.
The confusion often comes from mixing up lab diamonds with diamond simulants like cubic zirconia or moissanite, which are completely different materials that don't pass diamond tests. Lab diamonds are in an entirely different category.
Common Diamond Tests Jewelers Use
Let's walk through the tests jewelers typically perform and how lab diamonds respond to each one.
Thermal Conductivity Test
This is the most common quick test jewelers use. Diamond has exceptionally high thermal conductivityβit disperses heat faster than almost any other material. Handheld diamond testers measure how quickly heat moves through a stone.
Lab Diamond Result: Pass. Lab diamonds have identical thermal conductivity to natural diamonds. They'll register as "diamond" on these testers.
However, there's a catch: moissanite also conducts heat well and can sometimes fool basic thermal testers. That's why many jewelers now use dual testers that check both thermal and electrical conductivity.
Electrical Conductivity Test
Diamonds are electrical insulatorsβthey don't conduct electricity well. Moissanite, however, does conduct electricity. Modern testers check both thermal and electrical properties to distinguish diamonds from moissanite.
Lab Diamond Result: Pass. Lab diamonds are electrical insulators just like natural diamonds. They pass this test perfectly.
Hardness Test
Diamonds are the hardest natural material, rating 10 on the Mohs hardness scale. This means a diamond can scratch anything softer than it, but very few materials can scratch a diamond.
Jewelers rarely do actual scratch tests on customer jewelry (because it could damage the stone), but if they did, lab diamonds would perform identically to natural diamonds.
Lab Diamond Result: Pass. Lab diamonds have the same hardness and scratch resistance as natural diamonds.
Fog Test
This is an old-school test some people still use. You breathe on the stoneβif fog disappears immediately, it's likely a diamond. If fog lingers, it's probably glass or another simulant. This works because diamonds disperse heat so quickly.
Lab Diamond Result: Pass. Lab diamonds disperse heat identically to natural diamonds, so fog vanishes instantly.
Visual Inspection Under Magnification
Jewelers examine diamonds under 10x magnification or higher to look at clarity characteristics, cut quality, and other features. They're checking for inclusions, blemishes, and overall craftsmanship.
Lab Diamond Result: They look like diamonds because they are diamonds. Jewelers will see the same types of features they'd see in natural diamondsβinternal crystal structures, facet patterns, and any inclusions present in that specific stone.
What Makes Lab Diamonds Identifiable
If lab diamonds pass all the standard tests, how do gemologists tell them apart from natural diamonds? The answer requires advanced equipment and expertise.
Advanced Gemological Testing
Professional gemological laboratories use sophisticated equipment that most retail jewelers don't have:
Spectroscopy: Analyzes how the diamond absorbs and emits light across different wavelengths. Lab diamonds may show different patterns than natural diamonds due to trace elements or growth characteristics.
Magnification at High Power: Under very high magnification (much stronger than a standard jeweler's loupe), trained gemologists can sometimes identify growth patterns specific to HPHT or CVD processes.
UV Fluorescence: Some lab diamonds show different fluorescence patterns under UV light compared to natural diamonds, though there's overlap and this isn't a definitive test.
Phosphorescence: Some CVD diamonds show brief phosphorescence (afterglow) when UV light is removed. Natural diamonds rarely do this.
These are specialized tests that require expensive equipment and trained gemologists. Your local jewelry store doesn't perform these tests.
The Diamond Tester Scenario
Let's address a common concern: what happens if you walk into a jewelry store with your lab diamond and they test it?
When a jeweler uses a standard diamond tester on your lab diamond, it will read as "diamond." Period. The tester doesn't distinguish between lab and naturalβit only confirms whether the stone is diamond or not.
If a jeweler claims their tester shows your lab diamond isn't real, one of three things is happening:
- They're using faulty or low-quality equipment
- They're mistaken or not properly trained
- They're being dishonest to push a sale
A properly functioning diamond tester will always confirm a lab diamond as a real diamond.
Can Jewelers Refuse to Work on Lab Diamonds?
Some jewelers choose not to work with lab-grown diamonds due to personal preference or business policy. This is their right as business owners, though it's becoming less common as lab diamonds gain acceptance.
However, if a jeweler refuses because they claim a lab diamond "isn't a real diamond" or "won't test as real," they're either misinformed or being misleading. Lab diamonds absolutely test as real diamonds on standard equipment.
If you encounter resistance, you can:
- Show them the diamond's grading certificate from IGI, GIA, or another recognized lab
- Explain that lab diamonds have identical properties to natural diamonds
- Find a different jeweler who understands and works with lab-grown diamonds
Many jewelers now happily work with lab diamonds for sizing, cleaning, repairs, and settings.
Certification and Documentation
Every reputable lab diamond comes with certification from recognized gemological laboratories. These certificates clearly state that the diamond is laboratory-grown and provide all the same grading information as natural diamond certificates.
When a jeweler sees an IGI or GIA certificate for a lab diamond, they have official documentation of what they're working with. The certificate confirms:
- The diamond is genuine (not a simulant)
- It's laboratory-grown
- Its specific quality characteristics (the 4Cs)
- Often includes the growth method (CVD or HPHT)
This documentation removes any ambiguity about what the stone is.
Insurance and Appraisals
Lab diamonds can be insured and appraised just like natural diamonds. Insurance companies and professional appraisers recognize lab-grown diamonds as legitimate diamonds.
When getting an appraisal, make sure to:
- Disclose that it's a lab-grown diamond
- Provide the original grading certificate
- Use an appraiser familiar with lab diamonds
The appraisal will note that it's laboratory-grown and value it accordingly. Insurance coverage works the same way as for natural diamonds.
What About Resale?
While lab diamonds test as real diamonds, they do have lower resale value than comparable natural diamonds. This isn't because they're not "real"βit's market economics.
If you try to resell a lab diamond, buyers and jewelers will want to know its origin. They can verify it through:
- The grading certificate
- Advanced gemological testing if needed
- Laser inscriptions on the girdle (many lab diamonds have microscopic inscriptions)
The lower resale value reflects supply and demand, not legitimacy as a diamond.
The Bottom Line for Diamond Testing
Lab diamonds pass every standard test used in retail jewelry stores because they are chemically, physically, and optically identical to natural diamonds. The only way to definitively identify a lab diamond requires specialized gemological equipment found in professional labs, not your local jeweler's counter.
When you buy a certified lab-grown diamond from a reputable source, you're getting a real diamond that will test as such anywhere you take it. Standard diamond testers, thermal conductivity tests, and visual examination all confirm what lab diamonds are: genuine diamonds.
The distinction between lab and natural comes down to origin and price, not whether they're "real." Both are diamonds. One formed billions of years ago deep in the earth, the other formed in weeks in a high-tech facility. But hold them in your hand, examine them under a microscope, or test them with standard equipment, and you'll find they're the same material.
If anyone tells you otherwise, they're either working with outdated information or have reasons to steer you toward natural diamonds that have nothing to do with the actual properties of the stones.
Shop our collection of lab-grown diamond jewelry with confidence.