How to read a
Carat, colour, clarity and cut β the four measures behind every grade. Here is what each one means, and how to read it on a DGI report.
Carat
Weight, not size. One carat is 0.2 grams β but how it is cut decides how large it looks.
Colour
Graded D (colourless) to Z. The less colour, the rarer the stone.
Clarity
How free the stone is of inclusions, from Flawless (FL) to Included (I3).
Cut
How well the stone returns light. The one C made by human hands β and the one you see first.
The colour scale
From D to Z. Tap a grade to see what it means.
Colourless β no detectable colour. The rarest grade, and the most prized.
Near colourless β colour is hard to detect once the stone is set. Excellent value.
Faint β a slight warmth, visible to a trained eye against a white background.
Very light β a noticeable tint. Often chosen for a warmer look.
Light β a clear yellow tint. Beyond Z, colour is graded as fancy.
The clarity scale
Eleven grades, from flawless to visibly included. Tap one to learn more.
Flawless / Internally Flawless β no inclusions visible under 10Γ magnification.
VVS β very, very slight inclusions, extremely hard to see even under a loupe.
VS β very slight inclusions, difficult to see under 10Γ.
SI β slight inclusions, visible under 10Γ and sometimes to the naked eye.
Included β inclusions visible to the naked eye that may affect durability.
Why cut matters most
Cut is the only C shaped by human hands β and it decides how a diamond sparkles. We grade it from Excellent to Poor, with a Hearts & Arrows analysis where it is earned.
Excellent β maximum brilliance and fire.
Very Good β superb light return, a touch below ideal.
Good β bright and attractive, well priced.
Fair β a noticeable loss of brilliance.
Poor β light escapes; the stone looks dull.
Carat & size
Carat is weight β but buyers see size. Here is roughly how the two relate for a round brilliant.
| Carat | Diameter (round) |
|---|---|
| 0.25 ct | 4.1 mm |
| 0.50 ct | 5.2 mm |
| 0.75 ct | 5.9 mm |
| 1.00 ct | 6.5 mm |
| 1.50 ct | 7.4 mm |
| 2.00 ct | 8.2 mm |
| 3.00 ct | 9.4 mm |
Approximate values for a round brilliant β proportions vary.
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