The Four Cs Of Diamond Quality

When you begin looking for the perfect engagement ring you may come across the four Cs. Understanding the four Cs will help you to recognise the differences in diamond quality. To find out more about choosing a diamond visit our diamond buyer's guide


Diamonds are generally colourless or near colourless (they may have shades of yellow or brown.) A diamond which is completely colourless is more desirable than one which is slightly yellow. At Ernest Jones we use the Gemological Institute of America (GIA) scale to measure colour. A diamond which is graded D is colourless, and one which is graded Z will appear slightly yellow.

However, not all diamonds are colourless and you may want to choose an engagement ring with a touch of colour as a contemporary and stylish option.


Most diamonds will contain inclusions, flaws which are known as nature's 'birthmarks' or 'fingerprints'. Diamonds are rarely perfect, but the fewer inclusions, the more valuable the diamond will be. Most inclusions can't be seen by the naked eye meaning that they will not necessarily affect the beauty of your engagement ring however the clarity of the diamond is worth considering.


A diamond's carat measures the weight not the size of a diamond. A diamond with a large carat weight will make it a valuable diamond because of its rarity; however a diamond can appear larger than its actual weight depending on the way it is cut and set. If the engagement ring you choose is a diamond cluster ring the carat weight refers to the total weight of all the stones together.


A rough crystal is turned into a polished diamond by skilled craftsmen who aim to bring out the brilliance in each and every diamond. This is done by cutting a diamond with fine symmetry, proportions and angles which make good use of light by allowing it to be dispersed and reflected from one facet to another. A well cut diamond will sparkle and glisten. To find the perfect engagement ring, study the diamonds brilliance and beauty and spend some time choosing the right one for you.

Cut can sometimes refer to the shape of the diamond and there are many shapes available:

Round brilliant cut diamonds

The round brilliant cut diamond is a true classic and the most popular diamond shape there is. It suits any setting and ring style and is completely timeless.

Princess cut diamond

A princess cut diamond is a square shape with a brilliant cut; it gives a fresh modern look and is one of the most popular diamond cuts.

Cushion cut diamond

This is a hugely popular choice with the celebrities. It is a rounded square or rounded rectangular shape, which highlights the diamonds brilliance. This shape will often make use of big or fancy coloured diamonds.

Marquise cut diamond

A marquise diamond cut will maximise the carat weight and give a much larger looking diamond.

Heart cut diamond

A heart shaped diamond is a romantic choice and suits an engagement rings purpose of an expression of love. Emerald cut diamond

Emerald cut diamond

The emerald cut is another very popular choice. The shape is rectangular but can vary in length to width ratio. It is the special 'step-like' cut which highlights the diamonds clarity.

Oval cut diamond

Oval shaped diamonds can vary in length to width ratio. As one of the less commonly seen shapes in engagement rings it offers a unique style.

Pear cut diamond

Pear shaped diamonds will elongate the fingers and make them look slimmer.

Engagement Rings 4Cs Guide