A Guide to Diamond Jewellery

A Guide to Diamond Jewellery
June 25, 2016 sophie

Diamond Clarity, Cut, Carat & Colour

Diamonds are assessed and valued based on the Four Cs – clarity, cut, carat and colour. These terms are often used to describe diamond jewellery, so understanding what they mean will help you choose the right diamond and the right price. All of the 4Cs are important, so to attain the highest value, a diamond should have the best combination of all four.

Diamond Clarity


Clarity refers to the number of inclusions or ‘flaws’ a diamond contains. Almost all diamonds contain traces of non-crystallised carbon that are often invisible to the naked eye – diamonds that appear flawless to the naked eye are known as ‘eye-clean’.

Inclusions can interfere with the brilliance of the diamonds, causing it to appear dull. The greater the number or size of the inclusions, the lower the value of the diamond will be. Completely flawless diamonds are very rare, but you should expect a diamond to be at least eye-clean. Below are the standard ratings that you will see on this site.


Diamond Clarity Chart


Of the four ratings, VVs, Vs and Si no inclusions that are visible to the naked eye. These diamonds are commonly used in jewellery. Diamonds with a P rating are usually cut to a smaller size, to compensate for any inclusions. Small inclusions can also be hidden by clever setting of the diamond, so it is important to consider the overall appearance and value of your jewellery, making sure that you choose the right piece for you.

Diamond Cut


This criteria assesses the quality of the diamond’s cut, not its shape. A good cut should maximise the sparkle and scintillation (fire) of the diamond, making it even more beautiful. The cut is also assessed on the symmetry, polish and proportions of the diamond.

The proportions of a diamond are most important – if the diamond cut is too deep or shallow, light is not reflected correctly, compromising the brilliance of the diamond. It is important to keep this in mind when choosing the size of your diamond as well. A smaller diamond with a shallow cut will appear larger, but may have a lesser brilliance and therefore a lesser value.

There are many different types of cut, which are outlined in our Types of Stone Cut section. Whichever cut you chose, it should always make the most of the diamond’s natural beauty.

Diamond Carat

The carat measures the weight of the diamond, so the larger the carat weight, the bigger the stone. One carat is defined as 200 milligrams and has the abbreviation .ct. Diamonds of less than one carat are measured in points. Each point is a hundredth of a carat – 2mg.

It is important to remember that the carat measurement describes the weight of the diamond, not its diameter or height. The cut of a diamond can affect its diameter, and while too shallow a cut will increase the diameter of the diamond, it may compromise the brilliance of the diamond. For this reason you may find two diamonds that appear to be different sizes, but in fact have the same carat weight.

You may also see the phrase ‘total carat weight’ or the abbreviation ‘t.c.w.’ This refers to the total weight of all the diamonds included in one piece of jewellery, so it is often used for rings, earrings and necklaces set with many diamonds.

Diamond Colour

Pure and perfect diamonds are completely transparent. It is however, rare for diamonds to be completely colourless, and the colour of a diamond can both enhance or detract from its value.

Most ‘white’ diamonds actually have a range of yellow and brown tints. As intense heat and pressure are required to form diamonds, some stones may incorporate other minerals,which produces a slight colour.

White diamonds are graded using an alphabetical system that begins with ‘D’ and continues through the alphabet. Diamonds with the grade D are extremely rare and very valuable. The higher a diamond’s grade, the more colourless, rarer and valuable it is.

Diamond Colour Chart


Although coloured tints may make a diamond less valuable, vivid colours – known as ‘fancy’ diamonds can be very valuable. The colour should be strong and defined – the value of coloured diamonds often depends on the rarity of the colour. Pink and blue diamonds are highly desirable – one of the most famous diamonds in the world, the impressive Hope Diamond, has a wonderful grey/blue tint – while red diamonds are the rarest.

Understanding our Diamond Ratings

Each of Oproducts has a unique rating that tells you the colour and clarity of the stone. You will see this in the information underneath the description of each product. For example, our 0.25ct Diamond Solitaire 18ct Gold Ring has the rating J/K Si2. This means that its colour is between J and K, and its clarity is Si2. We can therefore understand that the diamond has no visible inclusions and has a good colour in the ‘top half’ of the colour grading system.

You will also see a rating for the carat of the diamonds. This tells you the total carat weight of the piece, so for example, our 1ct Sapphire & 1.28ct Diamond 18ct White Gold Flower Pendant contains one hundred and eighty four diamonds that weigh a total of 1.28ct.

Beneath this is a description of the diamond cut, whether ’round’, ‘oval’ or any other. You might notice a separate description of ‘Stone Colour‘ further down the list. This describes the general colour of the stones, not the diamond colour rating. This means that all diamonds are described as ‘white’, while colours such as ‘purple’ describe gemstones such as amethysts.

Using the Ratings to Choose Your Diamond

You can also use our colour, clarity, cut and carat ratings to choose your diamond jewellery. On the right-hand side of every page is a series of dropdown menus. By selecting a variable from the dropdown menu, you can view all the diamonds with a J/K Si2 rating, for example. You can then refine your search by other factors such as carat or the type of jewellery. When you select a criteria e.g. type of stone, the items will be arranged in order of price, so you can clearly see which pieces are available and find the right piece for you and your needs.

Diamond Cut

This criteria assesses the quality of the diamond’s proportions, not its shape in terms of ’round’ or ‘oval’. A good cut should maximise the sparkle and scintillation of the diamond, making it even more beautiful.

The quality of the cut is based mostly on its proportions – if the diamond cut is too deep or shallow, light is not reflected correctly, compromising the brilliance of the diamond. It is important to keep this in mind when choosing the size of your diamond . A smaller diamond with a shallow cut will appear larger, but will have a lesser brilliance and therefore a lesser value.

There is no one specific measurement that determines the quality of a diamond’s cut. It is assessed on a number of factors. Our certified diamonds are assessed by the International Gemological Institute. Standard grades are as follows:

Ideal Cut

Ideal Cut diamonds reflect nearly all the light that enters it. Approximately 3% of diamonds are given this grade.

Very Good Cut

Diamonds with a Very Good Cut reflect only slightly less than an Ideal Cut. They represent roughly the top 15% of all diamonds.

Good Cut

Reflects most of the light entering the diamond. Good Cut diamonds are significantly less expensive than the top two grades.

Fair Cut

A Fair Cut diamond is considered a high quality diamond but reflects less light that a Good Cut diamond.

Poor Cut

Poor Cut diamonds may be either too shallow or deep. Most of the light entering a diamond is lost through the sides and bottom of the stone.


To find our 9ct, platinum, 18ct yellow & white gold please click here.


Diamond Certification – A Buyer’s Guide

At Jewellery World we aim to give you maximum assurance and guarantee about the value and quality of your diamond jewellery, so that you can choose the perfect diamond with complete peace of mind.

Diamond certificates are important because they not only guarantee the specifications of your diamond, but allow you to compare similar diamonds, so you can be sure of the best value for money.

Our certificated diamond jewellery is assessed by the International Gemological Institute and each piece is accompanied by a full IGI certificate, so you can be completely certain of the fine quality and lasting value of your diamond purchase.

As always, we believe that the more information you have about your purchases, the better. Below you can find useful articles on the specifications of diamond certification, as well as a brief profile of the International Gemological Institute.

Understanding an IGI Diamond Report

Each of our certificated diamonds is accompanied by a Diamond Report which outlines and guarantees the specific characteristics of the diamond. Our diamond reports are issued by the International Gemological Institute, one of the world’s premier diamond grading institutions.

For more information, http://www.igiworldwide.com/index.php