Diamond Grading Explained: D/VVS vs H/SI and Why It Matters
Diamond Grading Explained: D/VVS vs H/SI and Why It Matters
When you shop for a diamond, letters and numbers follow you everywhere — D, VVS, SI, IGI. This guide explains exactly what they mean, why Finediam holds every stone to a D/VVS standard, and what that difference looks like in the real world.
When you begin shopping for a diamond — whether for an engagement ring, a pendant, or a pair of earrings — you will quickly encounter a set of letters and numbers that seem designed to confuse. D, VVS, SI, IGI. What do they mean? And why does Finediam hold every stone in our collection to a D/VVS standard when much of the industry accepts H/SI as perfectly adequate?
This guide answers those questions plainly, without jargon or sales pressure. By the end, you will understand exactly what you are buying — and why the grade on a certificate is not just a technicality. It is the difference between a stone that commands a room and one that quietly disappoints.
The 4Cs — The Universal Language of Diamond Quality
The Gemmological Institute of America (GIA) introduced the 4Cs framework in the mid-twentieth century to give buyers and sellers a shared vocabulary. Today, every reputable grading laboratory — including the International Gemological Institute (IGI), which certifies all Finediam stones — uses this system.
How precisely the diamond has been faceted. Cut governs how light enters, reflects internally, and exits the stone. A well-cut diamond returns light to the eye as brilliance, fire, and scintillation. It is the single most important factor in how a diamond looks.
How much — or how little — body colour the diamond carries. The scale runs from D (completely colourless) to Z (visibly yellow or brown). Finediam's minimum is D.
The presence, size, and position of internal characteristics (inclusions) and surface blemishes. The scale runs from Flawless (FL) down through VVS, VS, SI, and I grades.
The weight of the stone. One carat equals 0.2 grams. Carat affects size, but size alone does not determine beauty — a well-graded smaller stone will always outshine a poorly-graded larger one.
Why the 4Cs MatterUnderstanding these four factors gives you the tools to compare any two diamonds on equal terms — and to understand why two stones of identical carat weight can look and feel entirely different.
The Diamond Colour Scale — D to Z Explained
Colour in a diamond is graded by comparing the stone, face-down, against a set of master reference stones under controlled lighting. The scale begins at D and ends at Z. Here is what each tier means in practice.
Chemically and optically pure. No body colour is detectable, even by a trained gemologist under magnification. D is the pinnacle: a stone that appears as clear as a drop of water. This is the only tier Finediam uses.
These stones appear white to the untrained eye when viewed face-up in isolation. However, when placed beside a D-colour stone, the difference becomes visible. H, in particular, can show a faint warmth — especially in larger stones or yellow-gold settings where the metal amplifies any body colour in the diamond.
Body colour becomes progressively more visible. These grades are rarely used in fine jewellery and are not offered in the Finediam collection.
"A D-colour lab diamond costs less than a D-colour mined diamond — which means you can access the very top of the colour scale without the premium that mined stones command. There is no reason to compromise."
— FinediamThe Diamond Clarity Scale — VVS to SI Explained
Clarity describes what exists inside a diamond. During formation — whether natural or laboratory — tiny crystals, feathers, or clouds can become trapped within the stone. These are called inclusions. The clarity grade tells you how significant those inclusions are.
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FL / IFFlawless / Internally Flawless
No inclusions visible under 10× magnification. Exceptionally rare in both mined and lab-grown diamonds. The absolute peak of the clarity scale.
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VVS1 / VVS2Very Very Slightly Included ✦ Finediam Minimum
Inclusions are present but so minute that even a skilled grader struggles to locate them under 10× magnification. To the naked eye, a VVS stone is completely indistinguishable from a Flawless stone. This is our minimum standard at Finediam.
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VS1 / VS2Very Slightly Included
Inclusions are minor and difficult to see under magnification. Still eye-clean in almost all cases. A strong choice for buyers balancing budget and quality.
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SI1 / SI2Slightly Included
Inclusions are noticeable under 10× magnification and, in SI2 stones, can sometimes be seen with the naked eye — particularly in larger stones or step-cut shapes such as emerald or Asscher cuts, where the open facet structure offers less visual camouflage.
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I1 / I2 / I3Included
Inclusions are visible to the naked eye and may affect the structural integrity of the stone. Not used in fine jewellery of any quality standard.
Why Finediam Chose VVS as Its FloorA VVS stone is, to all practical purposes, perfect to look at. The inclusions that exist are invisible without specialist equipment. You are not paying for a theoretical ideal — you are paying for a stone that genuinely looks flawless in wear.
Finediam's Standard vs the Industry Standard
Much of the diamond industry — including many well-known online retailers — uses H/SI as their entry-level grade. This is not dishonest. H/SI stones are real diamonds with real beauty. But it is worth being explicit about what the difference looks like side by side.
| ◆ Finediam Standard | Industry Entry Grade | |
|---|---|---|
| Colour | ✓ D — Completely colourless | – H — Near-colourless, faint warmth visible beside D |
| Clarity | ✓ VVS — Inclusions invisible at 10× | – SI — Inclusions visible at 10×; sometimes naked eye |
| Certification | ✓ IGI certified, every stone | – Varies by retailer |
| Eye-Clean Guarantee | ✓ Yes, by grade definition | – Not guaranteed at SI2 |
| Lab-Grown | ✓ Yes — same physical properties as mined | – Varies by retailer |
The practical consequence of this gap is visible. Place a D/VVS stone beside an H/SI stone of the same carat weight and cut quality, and the D/VVS stone will appear brighter, whiter, and cleaner. In photography — and in the kind of editorial imagery that defines a luxury brand — that difference is significant.
We are not suggesting H/SI is a poor choice for every buyer. We are saying that at Finediam, we have chosen not to offer it, because our standard is the top of the scale. Browse our full collection of IGI-certified lab-grown diamond jewellery to see this standard in practice.
How IGI Certifies Lab Diamonds
Every Finediam diamond comes with an IGI (International Gemological Institute) certificate. IGI is one of the world's largest and most respected independent grading laboratories, with facilities across Europe, North America, and Asia.
The stone is submitted without any identifying information about its origin or price. This eliminates any possibility of grade inflation based on commercial pressures.
Trained graders assess the stone independently across all 4Cs. The certification process for a lab-grown diamond is identical to that for a mined diamond — the same rigour, the same criteria.
Results are cross-checked between graders, and only then is a certificate issued. For lab diamonds specifically, IGI also confirms the growth method — CVD or HPHT — and notes any post-growth treatments.
When you purchase from Finediam, the IGI certificate accompanies the stone. The unique report number can be verified directly on the IGI website — your independent confirmation that the grade on the listing is the grade on the diamond.
What IGI Transparency Means for YouThis level of transparency — growth method confirmed, treatments disclosed, grades independently verified — is part of what makes IGI certification meaningful. You know exactly what you have.
What This Means for Value
Lab-grown diamonds are physically, chemically, and optically identical to mined diamonds. The difference is origin, not composition. And because lab diamonds are produced without the extraction costs associated with mining, they are available at a fraction of the price of equivalent mined stones.
This creates an unusual opportunity. A D/VVS lab diamond — the grade that would represent the absolute pinnacle of a mined diamond collection — is accessible at a price point that, in the mined market, would typically buy you an H/SI stone.
Lab diamonds from Finediam are not a compromise. They are the most rational way to access the top of the grading scale — D colour, VVS clarity, IGI certified — without paying the historical premium that mined diamonds have commanded.
In other words: with a lab diamond from Finediam, you are not choosing between quality and budget. You are getting the quality that the budget previously could not reach. Explore our lab-grown diamond engagement rings or our full jewellery collections to find the stone that is right for you.
If you have questions about a specific stone, our grading certificates, or how to choose between cuts and settings, our team is available to help. Every Finediam purchase includes a consultation — because a decision this considered deserves a conversation.