Diamond Color Guide
Colour is one of the four Cs, and in a white diamond it is graded by its absence. The less colour a stone shows, the higher it grades and the more it is worth.
What is diamond color grading?
Laboratories grade white diamonds on a letter scale that runs from D, colourless, to Z, a light yellow or brown. It starts at D rather than A so it could not be confused with the looser systems it replaced.
A grader sets the stone face down beside a master set of diamonds of known grade and compares them under controlled, daylight-balanced lighting. Face down, the body colour shows without the distraction of light returning through the top.
Two laboratories, one scale
Natural stones we list are graded predominantly by GIA, lab-grown predominantly by IGI. Both use the same D–Z scale and the same letters, so an F on one report sits at the same point on the scale as an F on the other, whatever the stone's origin.
How strictly each laboratory applies the scale is debated in the trade. Read the grade as a reliable starting point, then judge the stone.
The color scale
Twenty-three grades in five groups. Each step is small; the groups are where the difference becomes something a buyer can see. Dots mark the grades of stones on hand this week.
- D, Colourless. In current stock: Round 1.50 ct lab-grown
- E, Colourless. In current stock: Emerald Cut 2.77 ct lab-grown; Pear Brilliant 2.00 ct lab-grown
- F, Colourless
- G, Near colourless
- H, Near colourless
- I, Near colourless
- J, Near colourless
- K, Faint
- L, Faint
- M, Faint
- N, Very light
- O, Very light
- P, Very light
- Q, Very light
- R, Very light
- S, Light
- T, Light
- U, Light
- V, Light
- W, Light
- X, Light
- Y, Light
- Z, Light
In stock now, by grade
D
None natural
E
None natural
F
None natural
G
None natural
H
None natural
I
None natural
J
None natural
None lab-grown
K to Z are sourced on request. Enquire about a lower grade
| Grade | Category | What it means |
|---|---|---|
| D–F | Colourless | No colour visible, even to a trained grader. The rarest and most expensive grades. |
| G–J | Near colourless | Colour is difficult to detect face up. The strongest value on the scale. |
| K–M | Faint | Slight warmth, most visible in larger stones and in white metal. |
| N–R | Very light | A noticeable tint. |
| S–Z | Light | A visible yellow or brown tone. |
The scale in current stock
Every grade on the scale above is a stone you can enquire on. These are this week's featured stones, each with its report grade.
How color affects appearance
A grade is set face down, where colour is easiest to see. Mounted and viewed face up, a diamond returns light through its top, and that brightness masks much of its body colour. Most people cannot place a near-colourless stone on the scale once it is set.
The setting changes what you see. Metal reflects into the stone, so its colour becomes part of the diamond's colour. A deep bezel of yellow gold warms a stone more than slim white prongs do.
White gold and platinum
Neutral, so any warmth in the stone shows against it. The natural partner for D to H.
Yellow and rose gold
Warm metal reflects into the stone and hides a warmer grade. J, and sometimes K, can look white against it — a D is partly wasted.
Color grade and price
Price falls as you move down the scale, and fastest across the colourless grades, where rarity is highest. A D costs noticeably more than an F that no one could tell apart from it once set.
Near-colourless grades, G to J, are where most buyers find the balance: colour very hard to see face up, at a clear saving on the grades above.
Natural and lab-grown
Lab-grown diamonds are more often available at D to F in larger sizes, at a price a comparable natural stone would not reach. The colour grade means the same thing on either; origin, not material, is the difference.
- D, Colourless
- E, Colourless
- F, Colourless
- G, Near colourless
- H, Near colourless
- I, Near colourless
- J, Near colourless
- K, Faint
- L, Faint
- M, Faint
- N, Very light
- O, Very light
- P, Very light
- Q, Very light
- R, Very light
- S, Light
- T, Light
- U, Light
- V, Light
- W, Light
- X, Light
- Y, Light
- Z, Light
How color interacts with the other Cs
Cut changes how colour reads. A well-cut stone returns more light face up, and that brightness makes a slight tint harder to notice. A stone cut deep or shallow leaks light and lets its body colour show.
Fluorescence can work either way. Medium to strong blue fluorescence can make a lower grade look whiter in daylight; in a few high-grade stones, strong fluorescence can look faintly hazy.
- Colour
- D to Z for white diamonds, or a fancy-colour description.
- Cut
- How the proportions return light. Graded for round brilliants only.
- Polish
- The finish of the facet surfaces.
- Symmetry
- How precisely the facets align with each other and the outline.
- Clarity
- Inclusions and blemishes, from FL down to I2.
- Fluorescence
- The strength of any glow under ultraviolet light.
How to read a grading reportDiamond carat guideDiamond cut guideDiamond clarity guide
Choosing the right color grade
Shape
Step cuts such as emerald and asscher have open facets that show colour plainly; stay higher on the scale. Brilliant cuts such as round and cushion hide a tint far better.
Carat weight
Colour is easier to see in a larger stone, simply because there is more of it. Moving up a grade matters more at two carats than at half a carat.
Setting metal
White gold and platinum suit D to H. Yellow and rose gold flatter I to K, and a very high grade is partly lost against them.
Budget
G to I is where most budget-conscious buyers do best: colour very hard to see once set, at a clear saving on colourless.
Origin
Lab-grown widens access to D to F at larger weights. Natural offers finite supply. Neither is the wrong choice; the grade means the same on both.
Frequently Asked Questions
What buyers ask most often about colour before choosing a stone.
See how colour trades off against the other Cs in the 4Cs calculator.
What is the best color grade for the money?
For most buyers, G to I. Mounted and seen face up, these grades are very hard to tell from colourless, and they cost noticeably less than D to F. In yellow or rose gold, J and sometimes K work just as well.
Can you see the difference between a G and an H color diamond?
Rarely, once the stone is set and seen face up. Face down under grading light, beside a master stone, a trained eye can. The difference between neighbouring grades is small; it becomes easier to see in larger stones and in step cuts.
Does diamond color affect durability?
No. Colour describes how a diamond looks, not how it wears. A D and a J diamond are equally hard and equally durable.
What is diamond fluorescence and does it affect color?
Some diamonds glow, usually blue, under ultraviolet light, including the ultraviolet in daylight. In lower colour grades, medium to strong blue fluorescence can make a stone look slightly whiter. In a small number of higher-grade stones with strong fluorescence, it can look faintly hazy. Reports grade its strength; judge the effect on the stone itself.
Do GIA and IGI grade color the same way?
Both grade on the same D to Z scale, by comparing the stone with master stones under controlled light, and the letters mean the same thing on either report. How strictly each laboratory applies the scale is debated in the trade, so treat any single grade as a starting point and look at the stone.
Shop Diamonds by Color
Choose a grade, and a shape if you have one in mind, to open the catalogue already filtered. Grades below J are sourced on request.
Enquire about a K grade or lower