The Diamond Colour Scale Explained: What D, E, F and "Near-Colourless" Mean
Why does the colour scale start at D? How are diamonds actually graded for colour, and what do colourless and near-colourless look like in real life? The scale explained.
The diamond colour scale runs from D to Z, and the first question everyone asks is: why D? The answer explains a lot about how colour grading works, and why small differences in grade rarely matter on the hand.
Why the scale starts at D
Before the modern system, jewellers used many inconsistent scales: letters, numbers, Roman numerals and terms such as "blue-white". When the Gemological Institute of America introduced its D-to-Z scale in the mid-twentieth century, it started at D to make a clean break from the old A, B and C grades that sellers had used loosely. It became the international standard.
How colour is graded
Graders place the diamond face-down on a white tray, under controlled daylight-equivalent light, and compare it with master stones of known colour. Viewing it face-down removes the distraction of sparkle and shows the body colour. Face-up and set in a ring, the difference between neighbouring grades is very hard to see.
What the groups mean
- D–F, colourless: icy white; even experts need master stones to separate them.
- G–J, near-colourless: look white face-up, especially when set; the best value for most buyers.
- K–M, faint: a visible warmth, attractive in yellow gold or vintage settings.
- N–Z: increasingly yellow or brown; beyond Z, strong colour counts as a "fancy" colour.
Lab-grown diamond colour
Most lab-grown diamonds sold today are in the colourless to near-colourless range. Some CVD stones grow with a brownish tint and are treated after growth to improve colour, which reports disclose. IGI grades lab-grown diamonds on the familiar D-to-Z scale; since October 2025, GIA describes them as "Premium" (D colour) or "Standard" (E–J) instead.
Colour and diamond size
The larger the diamond, the more body colour it shows, simply because light travels further through it. In small studs and pavé, H to J looks perfectly white. In a centre stone of two carats or more, especially in white gold, many buyers prefer G or better.
| Diamond | Looks white from |
|---|---|
| Pavé and accent stones | H–J |
| Studs up to about 0.5 ct each | H–J |
| Centre stone 0.5–1.5 ct | G–H in white gold, H–J in yellow gold |
| Centre stone over 1.5 ct | F–G in white gold, H–I in yellow gold |
Colour and shape
Round brilliants hide colour best, because their sparkle distracts the eye. Ovals, pears and marquises can show a little more warmth at their tips, where the stone is deepest. Emerald and Asscher cuts, with their open, mirror-like facets, show body colour most clearly, so it is worth going one grade higher for step cuts.
White, bright and certified
Why is there no A, B or C diamond colour grade?
The D-to-Z scale started at D to avoid confusion with older, loosely used A, B and C grades.
Can you see the difference between D and G?
Rarely, once set and viewed face-up. Side-by-side comparisons under lab lighting show it.
What colour are most lab-grown diamonds?
Mostly colourless to near-colourless, D to J.
Does a bigger diamond need a better colour grade?
Often, yes. Larger stones show more body colour, so a grade that looks white in a small stone may look warm in a large one.
Which diamond shape hides colour best?
The round brilliant. Step cuts such as emerald and Asscher show colour most.
