Guide
How to choose a diamond
Four characteristics — carat weight, colour, clarity and cut — describe every diamond on its certificate. We explain what you can really see and where you can save sensibly.
Carat — Weight
1 carat is 0.2 grams. Carat weight measures how much a stone weighs, not how large it looks from above.
- Prices rise sharply at ‘magic’ weights: 0.50, 0.70, 1.00, 1.50 and 2.00 ct. A 0.95 ct stone looks almost the same as a 1.00 ct stone, but costs considerably less.
- Elongated shapes (oval, pear, marquise) look larger than round stones of the same carat weight.
- A 1 ct round diamond measures about 6.4 mm across; 0.5 ct, about 5.1 mm; 2 ct, about 8.1 mm.
Colour — Colour
The scale runs from D (colourless) to Z (noticeably yellowish). D–J is the most common range for jewellery.
- G–H offers the best balance of price and appearance: once set, the stone looks colourless.
- For yellow and rose gold, I–J is usually enough — the warm metal complements the stone’s colour.
- ‘None’ or ‘faint’ fluorescence is a safe choice; strong fluorescence can make a stone look milky in sunlight.
- DColourless — highest colour grade
- EColourless
- FColourless
- GNear colourless — excellent value for appearance
- HNear colourless
- INear colourless, slightly warm
- JSlightly warm tone, well suited to yellow gold
- KNoticeably warm tone
Clarity
Describes tiny marks inside the stone (inclusions) and on its surface, viewed under 10× magnification.
- VS1–VS2 is a sensible choice: inclusions are usually invisible to the naked eye.
- SI1 can be ‘eye clean’ — it is worth checking a 360° video.
- In step-cut shapes (emerald, Asscher), inclusions are easier to see, so VS1 or higher is a better choice.
- FLFlawless — internally and on the surface
- IFNo internal inclusions
- VVS1Very, very small inclusions
- VVS2Very, very small inclusions
- VS1Very small inclusions, invisible to the naked eye
- VS2Small inclusions, usually invisible to the naked eye
- SI1Small inclusions, sometimes visible up close
- SI2Inclusions may be visible to the naked eye
Cut — Cut
The most important factor for brilliance: it determines how much light the stone reflects back to the eye.
- For round stones, choose an ‘Excellent’ (EX) or ‘Ideal’ cut.
- ‘Excellent’ or ‘Very Good’ polish and symmetry are a good standard.
- For fancy shapes, laboratories often do not grade cut — in that case, look at the proportions and video.
- IDIdeal
- EXExcellent
- VGVery good
- GGood
Certificate
How to read a certificate
A certificate is issued by an independent laboratory. We offer diamonds certified exclusively by GIA or IGI, two of the world’s most respected laboratories. It lists the shape, carat weight, colour, clarity, cut, proportions and measurements, along with a number you can check on the laboratory’s website. This number may also be laser-inscribed on the stone’s girdle, so you can match the certificate to the diamond.
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Natural or lab-grown?
Both are real diamonds — their origin and price differ, not their appearance. The choice depends on what matters more to you: rarity or a larger stone within the same budget.