The Diamond 4CsThe “Four C’s” – cut, colour, clarity and carat, must all be considered equally when comparing diamonds. According to Tiffany and Co, it is how the diamond is cut that will determine its defining characteristic.Cut: The only characteristic of a diamond not influenced by nature, the cut requires a true craftsman to ensure the optimum sparkle is created. The 57 or 58 facets (the tiny planes cut on the diamond surface) are angled and sized to dictate how light reflects and exits the diamond, an effect known as “fire”. Make the cut too deep or shallow and the diamond will be less brilliant.There are many shapes which diamonds can be cut into, the most popular are round cut, but others include emerald, the pear, the marquise, the princess, the oval, and the heart-shaped.Colour: The most valuable and rare colour is white diamonds, also known as colourless. We grade absolutely colourless diamonds at “D” and the scale moves up to “Z”, in between these two extremes, diamonds display subtle coloured tones. Diamonds with a very strong and distinct colour are extremely rare and called fancies.Clarity: When you are looking at diamonds, ask to use the jeweller’s loupe (magnifying eyeglass) and you will see the small “inclusions” which look like small clouds or feathers but usually invisible to the naked eye. These are not necessarily faults but can affect the diamond’s fire. Make sure the stone is graded SI1 (Slightly Included 1) or better, and most expensive, IF (Internally Flawless), worst is I3 (Imperfect 3).Carat: The weight and size of a diamond is measured by carat. A carat is equal to 0.2gm, or 200mgm. A carat is divided into 100 smaller units called points. For example, a quarter of a carat is 25 points. The average size of an engagement-ring diamond is between one carat and half a carat. Just to confuse things, the unit of purity for gold is called karat, but these two should not be confused.To ensure you are being sold a “real” and untreated diamond make sure that the diamond is a “cert stone” – a diamond that has been assessed, graded and coded with a laser by an independent gemmological laboratory. Ensure the certificate is universally recognised, the most internationally recognised is GIA (the Gemmological Institute of America), following that other popular certificates are HRD, IGL, EGL and AGS. All of the diamonds I use have a GIA certificate which you will receive with the finished item of jewellery.