Carat

This refers to the weight of a diamond. One carat equals one fifth of a gram. It can also be divided into 100 points. Generally, the larger the carat, the more rare and valuable the diamond. Two diamonds of the same weight, however, can have very unequal values, depending on their clarity, colour and cut. Cut and mounting can make a diamond appear larger than its actual carat weight. Your local Prouds diamond expert will help you find the best setting to maximise the size and beauty of your stone.

Clarity

Most diamonds contain inclusions - natural identifying characteristics such as minerals or fractures. These are known as nature's "birthmarks" or "fingerprints" and may look like tiny crystals, clouds or feathers. The fewer the inclusions, the greater the clarity and the more valuable the diamond.Inclusions are usually invisible to the naked eye. However, their number, size and location can affect the flow of light through a diamond, causing some of the sparkle to be lost. Diamonds with inclusions that are visible to the naked eye are graded I1 - I3. Those with small inclusions are graded SI1 - SI2, those with very small inclusions are graded VS1 - VS2 and diamonds with very very small inclusions are graded VVS1 - VVS2. Those rare diamonds with no inclusions are called flawless (FL) or internally flawless (IF).

Colour

Although many diamonds appear colourless, most contain subtle tones of yellow or brown. The closer a diamond is to having no colour, the more valuable it is. Diamond colours are graded from D, continuing through the alphabet to Z. Truly colourless diamonds (graded D) are treasured for their rarity. While still beautiful, lower graded diamonds are less rare.Choice of colour comes down to personal taste. White colours (D-J) look particularly good set in white gold or platinum; warmer colours (K-Z) are stunning set in yellow gold. Colour differences between stones can be very subtle. To appreciate the differences, ask your Prouds experts to compare the stones side by side.

Cut

The cut indicates the physical shape of the diamond and refers to the angles and proportions a skilled craftsmen creates in the stone, releasing its fire and sparkle. It is the only one of the 4Cs not determined by nature. The cut of the stone causes light to be dispersed and reflected from one facet to another. A well proportioned cut allows the greatest amount of fire and sparkle to be reflected. If a diamond is cut too deep or too shallow, light escapes through the side or the bottom and the display will be less brilliant. A well cut diamond is more valuable than a poorly cut stone of the same weight, clarity and colour. The traditional diamond shape is round brilliant. Since a round diamond is symmetrical and capable of reflecting nearly all the light that enters, it has the greatest brilliance of all shapes. The six most popular cuts are marquise, emerald, princess, pear, oval and heart.

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