Diamond Colour Guide

What is diamond colour?

Diamond colour is arguably the second most important characteristic to consider when buying diamond jewellery. The highest quality diamonds are colourless, while diamonds of lower quality are noticeably more pale yellow in colour.

To measure the colour (or lack of) in a diamond, there is an industry standard colour grading system set out by the GIA (Gemological Institute of America) which gives a lettered scale and brief description of a diamond's colour. You will see the grading shown online in jewellers and as part of a diamond certification document.

Like most classifications of a diamond, choice is down to personal preference. For example, some diamonds present with a slight tint of yellow or brown, which can look great when set in yellow or rose gold but may not look so good in a white metal like platinum. Most diamonds you will find in a retail jeweller will be graded or certificated using the GIA grading scale from letters 'D' to 'I', with the exception of fancy coloured diamonds.


What are fancy coloured diamonds?


Unlike diamonds in the standard GIA colour scale described below, fancy or 'colour' diamonds are rare diamonds that exhibit different colours of the spectrum that fall outside of the standard 'colourless' scale.

For example, fancy diamonds can come in all colours of the spectrum, most commonly; blue, green, pink, and red, but, some are simply tinted yellow more than a 'Z' grade 'colourless' diamond and are therefore fully fledged yellow diamonds.

How to check the colour of a diamond


To look at the colour of a diamond, the best way is to use your eyes, no tools required. This may sound like a no brainer and a little too easy but if a diamond is tinted with colour it will be noticeable with the naked eye! The best way is to compare the underside of the diamond to a white surface like a piece of paper.

It won’t be as obvious from the top of the diamond as you will just see the sparkle from the top, but from the underside the colour will be more obvious.

GIA Diamond Colour Scale

The colour grading system starts with the letter D and runs right through to Z. The grading system starts at the letter D because the GIA (Gemological Institution of America)wanted to start fresh with a new industry standard scale so disasociated themselves from existing colour scales using the D - Z scale. Here's how the grading scale works:


How Shape Can Affect Colour

Different diamond shapes can be more forgiving than others when it comes to diamond colour grades. To help you rate the significance of colour in each diamond shape, we've made our own colour scale from 1 to 10. 1 being the least important factor and 10 being the most important factor to think about if you're choosing that particular diamond shape.


Least Affected By Colour


Due to the exceptional sparkle of a round brilliant cut diamond, a slightly lower colour grade won't be as obvious as the sparkle and brilliance will hide it.

Affected by Colour


Emerald or Asscher cuts have a more mirror-like finish which shows diamond colour more obviously as there are less facets to disguise the tinting.

Most Affected By Colour


Long fancy cuts such as marquise, pear or oval can have long facets in them, meaning that the colour can be seen more obviously in certain sections of the diamond.

Which Is The Best Diamond Colour?

The highest colour grade and therefore most expensive colour grade money can buy is a 'D' colour. But, when it comes to choosing the best diamond colour you won't go wrong coming down a few grades from 'D' and saving yourself some money. To the naked eye there is very little difference in colour from a 'D' to a 'H' grade diamond.

Most Popular

The most popular grade is a 'G' or 'H' as this gives a good saving while also not showing visible signs of tinting so you'll get a beautiful colourless diamond to the eye without paying too much of a premium. Like most facets of a diamond, going to see it personally will ensure you pick the best one.

For the Savvy

You will save roughly 10% between each grading bracket if all other diamond facets stay the same. So if carat, clarity, cut and shape remain the same and you choose an 'F' rather than a 'D' you'll save approximately 10%.

To help with your decision, here's the GIA scale illustrated with an illustration of tint to give you an idea of how colour can impact the look of a diamond:

D-F Colour

These are the highest colour grades and visually there is not much of a difference between D through F (unless you are a trained gemmologist!)

  • Cost:Most expensive but most visually stunning.
  • Ideal for:Platinum or white gold to best accentuate the diamond sparkle.

G-J Colour

Visually there is not much of a difference from the above bracket. But you will see a slight difference in tint when comparing to D-F.

  • Cost:High but best value for a colourless diamond, approximately 10-20% off a 'D' grade.
  • Ideal for:White metals still give extra sparkle to these grades

K-M Colour

These grades will look slightly yellow or brown in tone to the naked eye, and more obviously if looking through the underside of the diamond.

  • Cost:Lower end of the budget, approximately 20-30% off a 'D' grade.
  • Ideal for:Yellow or rose gold which complements the diamond tone.

N-R Colour

Diamonds through these colour grades are noticeably tinted in colour, although not necessarily in a bad way when paired with the right metal.

  • Cost:Lower end of the budget, approximately 30-40% off a 'D' grade.
  • Ideal for:Coloured metals such as rose and yellow gold.

S-Z Colour

Diamonds in these colour grades start to look like fancy coloured diamonds. Often people choose these grades for an alternative look.

  • Cost:Lowest, approximately 40-50% off a 'D' grade.
  • Ideal for:Someone looking for a less traditional diamond appearance.

Expert Buying Tips:

  • The colour of a diamond is most noticeable when it is loose or unset, so it may be difficult to grade a set diamond.
  • If you are looking for a halo or diamond shoulder ring it would be advisable to stick to graded D-J. With the smaller diamonds set alongside the central one it can make the diamond look slightly tinted if surrounded by smaller diamonds.
  • Lower diamond grades from J-Z will still sparkle and look good, but will look best set in a single stone design and will look even better if set in a metal with a warmer tone like yellow gold. The sharp whiteness of platinum or white gold can be quite harsh next to a slightly tinted diamond.

Key things to remember:


  • D-F grades are the highest colour grades money can buy so expect a premium on diamonds at this level.
  • Round brilliant cuts are the most forgiving cut when it comes to disguising a lower colour grade due to their sparkle.
  • G-J colour diamonds are the most popular and provide the best value for white/colourless diamonds without having to pay the premium of D-F grade stones.
  • Consider choosing a lower colour grade of diamond set into yellow or rose gold. The warmer metal tones can complement a slightly tinted diamond and still look amazing.
  • If opting for a diamond which is J colour or above it will look better set on its own. Having a halo or shoulder diamonds surrounding it can make the diamond look discoloured by comparison.
  • No one else will know the exact spec of your diamond (unless you tell them) so if you love it don't be put off by a lower colour grade if it is what you want!

Have A Question?

Contact us by phone at 0141 221 5855 or by email at [email protected]. We love our work and will be happy to help you with your query, we can also book a convenient time for a consultation to find the exactly what you need.


Simon Porter

Director, James Porter & Son

  • Image
  • Image
  • Image

Simon is the 5th generation Porter to look after the day to day running of the James Porter & Son store since its inception in 1858. Working alongside his father since 1995 and eventually taking over the reins full time in 2007.

Back to top

  • Engagement Rings

    Explore our curated designs with the help from our expert team.

    60 min
  • Wedding Rings

    Find the perfect wedding rings for you and your partner.

    60 min
  • Luxury Jewellery and Gifts

    Our team of dedicated experts will help you find the perfect piece of jewellery for any occasion.

    60 min
  • Bespoke Rings

    With a dedicated team of experts, we will help you create the perfect one of a kind ring for any occasion.

    60 min
  • Watches

    Explore and try on any watches you have had your eye on with help from our team of horological experts.

    60 min
  • Ring & Jewellery Drop-off

    Drop-off your rings or jewellery for cleaning, resizing, repairs and more

    15 min
  • Watch Drop-off

    Drop-off your watches for battery replacements, strap resizing, repairs and more.

    15 min

Select time for date:

    Booking Summary

    Engagement Ring 60 Min
    Tuesday 28 November 10:30 am


    Argyll Arcade
    G2 8BG
    0141 221 5855 (Option 2)
    Mon-Sat 09:30 - 17:30
    Sunday 11:00 - 17:00