What Is a Natural Diamond: direct answer
A natural diamond is pure carbon that crystallised deep in the Earth’s mantle under extreme pressure and heat, and was carried towards the surface by volcanic activity in rock formations known as kimberlite pipes. It was then mined, cut and polished.
That is the whole of the definition, and the word doing the work is natural — it describes origin, not quality. A natural diamond is not automatically better than a laboratory-grown one, and a laboratory-grown diamond is not an imitation. Both are diamond. What separates them is where the crystal came from, and that must be disclosed.
It is also worth being precise about what a natural diamond is not. Cubic zirconia and moissanite are different materials entirely — simulants that resemble diamond to the eye but differ in composition, hardness and optical behaviour. A laboratory-grown diamond is diamond; a simulant is not.
What this term or grading factor means
South African buyers encounter several terms in this area, and they are not interchangeable. Getting them straight is the most useful thing you can do before comparing anything.
| Term | What it is | How to treat it |
| Natural diamond | Carbon crystallised geologically, then mined | Origin stated on the report and the invoice |
| Laboratory-grown diamond | The same material, produced in a controlled environment | Real diamond; origin must be disclosed |
| Diamond simulant | A different material that resembles diamond | Cubic zirconia, moissanite and others — not diamond |
| Treated diamond | A natural stone altered to improve colour or clarity | Legitimate, but must be disclosed |
| Composite or fracture-filled | A stone with fractures filled to improve appearance | Requires disclosure; affects durability and cleaning |
The last two rows matter more than most buyers realise. A treated natural diamond is still a natural diamond, but treatment changes what the stone is and should be disclosed on the report and on the invoice. Fracture-filled stones in particular need special care during cleaning and repair, and any jeweller working on one needs to know.
How it is assessed or identified: natural origin, grading report, quality factors and provenance claims
Natural origin. Distinguishing a natural diamond from a laboratory-grown one is not something the eye can do, and it is not something a jeweller can do reliably with a loupe. It requires instrumentation that examines characteristics such as growth structure and trace elements, and it is done routinely by the major grading laboratories. This is precisely why the report matters: it is the practical mechanism by which origin is established and recorded.
The grading report. An independent report from a recognised laboratory identifies the stone, states its origin, and grades it on the 4Cs — cut, colour, clarity and carat weight. It will also record any treatment and note fluorescence. GIA’s grading methodology sets out how each characteristic is assessed, and GIA’s guide to report types explains what the various report formats cover.
Quality factors. Within natural diamonds, quality is the 4Cs and nothing more mystical than that. Cut governs how the stone returns light and is the grade most responsible for whether a diamond looks alive. Colour and clarity are graded on defined scales. Carat is weight, not size — two stones of equal weight can present very differently depending on how they are cut.
Provenance claims. Claims about a specific mine, a country of origin, or ethical and conflict-free sourcing should be supported by documentation rather than asserted in conversation. We do not publish sourcing or ethical claims we cannot evidence, and we would suggest asking any seller who makes them what paperwork stands behind the claim. A story without documentation is a story.
What buyers should look for
Whatever you are buying, these checks apply.
- An independent grading report from a recognised laboratory, issued for the specific stone rather than a generic grade range.
- Origin stated explicitly — natural or laboratory-grown — on both the report and the invoice.
- A laser inscription on the girdle matching the report number, which you can ask to see under magnification.
- Online verification. The major laboratories offer a report-check service. Use it yourself rather than relying on the printed copy in front of you.
- Treatment disclosure. Ask directly whether the stone has been treated in any way, and expect a documented answer.
- The cut grade or, for fancy shapes, the measured proportions, since no overall cut grade is issued for shapes other than the round brilliant.
- An independent insurance valuation, obtained separately from the sale.
How it affects appearance, quality or price
Appearance. Origin has no bearing on appearance. A natural and a laboratory-grown diamond of the same shape, weight and grades look the same, because they are the same material with the same optical properties. Anyone claiming to spot the difference by eye is mistaken.
Quality. Both are graded on identical scales, and both come in the full range from excellent to poor. “Natural” is not a quality claim. A poorly cut natural diamond will look worse than a well-cut laboratory-grown one, every time.
Price. This is where origin has its clearest effect. Natural and laboratory-grown diamonds trade in separate markets, and at any given specification the difference is substantial. We do not publish figures — they move — but the direction is consistent and it widens as carat weight increases. See natural diamond prices and how the two compare.
On value over time, we make no claims in either direction and we are not financial advisers. If that question is central to your decision, our page on whether natural diamonds hold value sets out the structure of the second-hand market honestly, and recommends taking independent advice.
Common misunderstandings and mistakes
These come up constantly, and each of them costs buyers money or confidence.
- “Lab-grown diamonds are fake.” They are not. They are diamond. Simulants such as cubic zirconia and moissanite are the different materials.
- “Natural means higher quality.” It means a different origin. Quality is the 4Cs, and both origins span the whole range.
- “A jeweller can tell by looking.” Reliable origin determination needs instrumentation, which is why the report exists.
- “Carat is a measure of size.” It is a measure of weight. Cut determines how much of that weight you actually see face-up.
- “Flawless is worth paying for.” Above eye-clean, and depending on the shape, you are buying a grade on paper rather than a visible difference.
- “Any certificate will do.” Grading standards differ between laboratories. The same letters from two different reports do not necessarily describe the same stone.
- “Treatment is a scandal.” It is not, provided it is disclosed. Undisclosed treatment is the problem, not treatment itself.
What to do next before buying
Decide first whether origin matters to you, and be honest about why. If it does, specify natural and insist the report says so. If it does not, comparing both origins at the same grade combination will show you exactly what the difference costs.
Then focus on cut. Of the four grades it is the one that determines whether the diamond looks beautiful, and it is the one most often traded away to reach a carat weight.
Continue to natural diamonds in South Africa for the category, natural diamond rings for finished pieces, or lab-grown vs natural diamonds for the full comparison. The 4Cs explained covers the grading in detail.
Ask us what the report should say
Bring us a stone you are considering, or a specification, and we will tell you what the documentation ought to show and what to check before you pay for anything.