Buying a diamond is a significant investment, and for many people, understanding exactly what they own is just as important as the beauty of the stone itself.
Today, consumers have more choice than ever. Alongside natural diamonds, laboratory-grown diamonds are widely available and can look virtually identical to the unaided eye. Both can be beautiful, durable and suitable for jewellery — but they are not the same type of diamond, and their values, origins and market characteristics can be very different.
So, if you already own a diamond ring, or you are considering buying one, how can you tell whether the diamond is natural or laboratory-grown?
The short answer is: you generally cannot tell reliably by looking at the diamond or using a basic diamond tester.
Why Natural and Laboratory-Grown Diamonds Look So Similar
A laboratory-grown diamond is not simply a diamond imitation.
Unlike cubic zirconia or many diamond simulants, laboratory-grown diamonds have essentially the same chemical composition and crystal structure as natural diamonds. They are created using advanced technology that replicates some of the conditions under which diamonds form naturally.
The two main laboratory-growing technologies are:
- HPHT — High Pressure High Temperature
- CVD — Chemical Vapour Deposition
Because laboratory-grown diamonds are genuine crystalline diamond material, many traditional diamond testing instruments will identify them as diamond.
That is where the confusion can begin.
A tester telling you that your stone is a diamond does not necessarily tell you whether it is a natural diamond or a laboratory-grown diamond.
What Can a Basic Diamond Tester Tell You?
Many jewellery stores, pawnbrokers and consumers use handheld diamond testers.
These devices are useful as a first screening tool. Depending on the type of tester, they may measure properties such as thermal conductivity or electrical conductivity to determine whether a stone behaves like diamond.
For example, a basic thermal diamond tester may indicate:
“Diamond.”
That can be useful information — but it does not necessarily mean:
“Natural diamond.”
A laboratory-grown diamond can also test as diamond because it is diamond.
The limitation is important
A basic diamond tester is generally designed to distinguish diamond from certain simulants. It is not a definitive origin test.
This means a consumer should be cautious about relying on a handheld tester as proof that a diamond is natural.
Some more advanced screening instruments can identify characteristics associated with laboratory-grown diamonds and can help separate natural diamonds from laboratory-grown stones. However, screening is still different from issuing an independent grading report.
Can You Tell by Looking at the Diamond?
In most cases, no.
Natural and laboratory-grown diamonds can both display:
- Excellent brilliance
- Fire and scintillation
- Similar colour grades
- Similar clarity characteristics
- Similar cuts and proportions
- Exceptional hardness
To the unaided eye, even an experienced jewellery professional may not be able to determine the origin of a diamond simply by examining it.
This is particularly important when buying a second-hand ring, inherited jewellery or a diamond without documentation.
The fact that a diamond looks beautiful does not tell you whether it is natural or laboratory-grown.
What About a Loupe?
A jeweller’s loupe can reveal inclusions and other characteristics inside a diamond, and an experienced gemmologist may sometimes recognise features that suggest a particular origin.
However, a loupe is not a substitute for laboratory testing.
Laboratory-grown diamonds can contain distinctive growth features, and natural diamonds can contain a wide variety of inclusions and characteristics. Some observations can raise suspicion or indicate that further testing is required, but visual examination alone should not be treated as definitive proof of origin.
What About the Laser Inscription?
One of the most useful things a consumer can check is the laser inscription on the diamond’s girdle.
Many diamonds accompanied by a laboratory report have a microscopic inscription on the edge of the stone corresponding to the report number.
If your diamond has a report, a jeweller or gemmologist can use magnification to examine the girdle and compare the inscription with the report.
However, consumers should understand that an inscription alone is not proof of a diamond’s identity. It needs to correspond with the actual laboratory report and the characteristics of the stone.
If there is no report, an inscription by itself provides very limited protection.
Why an Independent Diamond Laboratory Report Matters
This is where an independent gemmological laboratory becomes extremely important.
A professional laboratory can examine the diamond using sophisticated equipment and gemmological techniques that go far beyond a basic handheld tester.
Depending on the laboratory and the examination required, testing may assess characteristics such as:
- Natural or laboratory-grown origin
- Diamond quality
- Colour
- Clarity
- Cut and proportions
- Fluorescence
- Inclusions
- Treatments
- Growth characteristics
- Other identifying features
The result is an independent report that documents the characteristics of the stone.
This creates something extremely valuable for the consumer:
A documented identity for your diamond.
Why This Protects You When Buying a Diamond
Imagine purchasing a diamond ring today for a significant amount of money.
The salesperson tells you that the centre stone is a natural diamond.
You take the ring home, but there is no independent laboratory report.
Years later, you decide to sell, upgrade or insure the ring.
How do you prove what the diamond actually is?
This is where problems can arise.
Without independent documentation, you may be relying on:
- The original seller’s description
- An old invoice
- A valuation
- Your own understanding of the stone
- A basic diamond tester
- A verbal representation of the diamond’s origin
None of these provides the same level of independent evidence as a recognised laboratory report.
A Valuation Is Not the Same as a Diamond Grading Report
This distinction is often misunderstood.
A valuation primarily addresses the monetary value of an item for a particular purpose, such as insurance or estate planning.
A diamond grading report documents the gemmological characteristics of the diamond.
These are different services.
For example, a valuation might state that a ring has an estimated replacement value of a particular amount. It does not necessarily establish, to the same level of gemmological certainty, whether the centre diamond is natural or laboratory-grown.
For consumers buying a significant diamond, having the diamond independently examined and documented can therefore be extremely important.
Natural Diamond or Laboratory-Grown Diamond — Why the Difference Matters
There is nothing inherently wrong with choosing a laboratory-grown diamond.
For some consumers, a laboratory-grown diamond may provide the opportunity to purchase a larger or higher-specification diamond for a particular budget.
Others specifically want a natural diamond because of its geological origin, rarity, history and established place within the natural diamond market.
The important point is choice and transparency.
A customer should know exactly what they are buying and what they are paying for.
A laboratory-grown diamond should be represented as laboratory-grown.
A natural diamond should be represented as natural.
The consumer should never have to guess.
What Should You Do Before Buying?
If you are purchasing a significant diamond, DCLA recommends asking a few straightforward questions:
1. Is the diamond natural or laboratory-grown?
Do not rely solely on verbal assurances.
2. Is there an independent laboratory report?
Ask to see the original report and check that it corresponds with the diamond.
3. Does the diamond have a report number inscription?
If so, have the inscription checked under magnification.
4. Does the report describe the actual diamond?
The report should correspond to the stone’s identifying characteristics.
5. If there is no report, can the diamond be independently examined?
For a valuable diamond, independent verification can provide significant peace of mind.
What If You Already Own a Diamond Without a Report?
Don’t panic.
If you have an engagement ring, inherited diamond, family jewellery or a diamond purchased many years ago without documentation, it does not automatically mean there is a problem.
You can have the diamond examined by a suitably qualified gemmological laboratory.
Professional testing can help establish whether the stone is natural or laboratory-grown and document its characteristics.
This can be particularly valuable if you are considering:
- Selling the diamond
- Upgrading your jewellery
- Obtaining insurance
- Estate planning
- Dividing an inheritance
- Purchasing a replacement
- Establishing what you actually own
The Bottom Line: Don’t Test the Diamond — Verify It
A basic diamond tester can be useful.
A loupe can be useful.
An experienced jeweller can be useful.
But none of these should be confused with a comprehensive independent laboratory examination.
A diamond tester can tell you that a stone behaves like diamond. It does not necessarily tell you whether that diamond came from the earth or was grown in a laboratory.
When the origin and quality of a diamond matter, independent laboratory testing and documentation provide the strongest form of consumer protection.
DCLA — Independent Diamond Expertise
The Diamond Certification Laboratory of Australia (DCLA) provides professional diamond and gemmological services designed to give consumers, jewellers, insurers and industry professionals greater confidence in the diamonds they buy, sell and own.
Whether you are purchasing a new diamond, checking an existing engagement ring or looking to understand the characteristics and origin of a family diamond, independent examination can give you something a simple tester cannot:
documented confidence in what your diamond actually is.
When it comes to a significant diamond purchase, don’t simply ask, “Does it test as a diamond?”
Ask the more important question:
“Can I independently verify exactly what this diamond is?”
