How can the quality of a diamond be determined?

When making any large investment, knowing that what you’re purchasing is of high quality and up to standards that match the item’s price tag is key. Luckily, when buying diamonds there are several indicators of quality available within the stone’s grading and certification, so that as a buyer you can determine if the diamond in question is of high enough quality for the piece it’s intended for.
These indicators of quality are broken down into what we call the 4 C’s – carat, cut, colour and clarity. If you don’t yet know what it all stands for, these categories and gradings can be a little overwhelming, which is why we’ve created this short guide to help you piece together the information you have about a diamond and find out how it all adds up to determine the quality.

Alongside this, legitimate diamonds should come with a certificate from a reputable, independent diamond grader or lab. When browsing through the Diamond Brokers ‘Diamond Finder’, you’ll notice that all of our diamonds have been certified by either GIA, AGS, HRD or IGI.


Carat refers to the weight of the diamond, but it’s important to know that this alone does not determine the value or size of the a stone. A lower carat weight with a superior cut, clarity or colour will be worth more than a diamond selected solely based on larger carat weight.

When comparing diamonds of similar clarity, cut and colour though, the carat weight becomes much more significant the larger the stone. This is due to the rarity of larger diamonds, so you’ll notice that the value is much higher per carat. For example a 2ct diamond is generally over double the cost of a 1ct that has a similar clarity, cut and colour grading.



The closer the diamond is to being colourless, the higher the value and quality. The colour scale is based on 23 grades ranging from D to Z and is broken down into the following subcategories:

D-F = Colourless, G-J = Near Colourless, K-M = Faint, N-R = Very Light, S-Z = Light.

A ‘D’ scale diamond will be entirely transparent, thoroughly rare and quite costly. Tinges of yellow and brown can appear in stones lower down the scale and, unless dealing with a rare coloured stone, this will bring down the value. It’s worth noting that many colour distinctions can be very subtle and not visible to the naked eye.


It’s the cut of a diamond that will determine the ultimate brilliance. As a general rule, the higher the cut grade, the brighter the diamond. There is a delicate balancing act required during diamond cutting, by shaping, positioning and angling each facet with symmetrical precision to maximise sparkle, the cutter must also take care not to sacrifice too much of the diamond’s size.

A shallow diamond will lose light out the bottom and a deep cut will allow light to exit at the sides of the diamond, however a proportional cut returns light through the top, creating optimal dazzle. This of course will add value and expense to a diamond with a proportional cut.



Clarity is the measure of how flawless a diamond is. Natural blemishes occur externally and internally during the formation of a diamond, and so when a stone appears to be truly flawless under 10-power magnification, their rarity makes them extremely valuable.

Although most diamonds will be flawed in some way, their sparkle can often disguise imperfections and have little impact on the visual appearance of the diamond. Clarity ratings are based on world industry standard scales as shown below:

IF = Internally flawless, VVS1-2 = Very very slight inclusions ,SI1-2 = Eye clean but slight inclusions, PK1-2-3 = Visible to the naked eye


The quality of the diamond that you opt for will most likely come down to your budget, but it is worth bearing these factors in mind to make sure that you are getting the quality that you pay for.

Explore our range of diamonds to familiarise yourself with the grading system and eventually find the diamond that’s perfect for you.