The Four Cs
Diamonds are graded on their cut, colour, clarity and carat. These four factors are known as the 4 Cs, and it is these attributes that affect the value and quality of a diamond.
The cut of a diamond describes the symmetry, proportions and finish of a polished diamond. There is an art and science to diamond cutting which requires the skills and workmanship of a master cutter to bring a diamond from a rough mined stoned to a finished, polished diamond. Diamond cut is not to be confused with the shape of the stone, but rather refers to the quality of workmanship and angles that reflect the maximum amount of light and create the best sparkle.
The above sketches illustrates how light reflects and returns based on the cut of the diamond.
It’s important not to confuse the cut of a diamond with its shape. However, there are a number of shapes that a diamond can be cut to, depending on the nature of the original stone.
The traditional shapes which diamonds are cut to are as follows:
The Round Brilliant and Princess cut (square shaped) diamonds are the most popular shapes. Out of 100 diamond shapes produced, round brilliants make up 80-85% whereas 5-10% will be princess cut diamonds. The remainder will be a variety of all the other shapes including; oval, marquise, heart, emerald, pear, asscher, cushion, trillion, baguette and radiant diamonds.
The aptly named round brilliant, reflects the maximum light and sparkles more than any other shape. Also, because 50% of the rough diamond is lost when cutting them, they are also slightly more expensive than other shapes.
Although diamonds are essentially colourless, the term 'colour' refers white diamonds which are graded on a scale using the letters of the alphabet from D to Z.
The letters are based on the level of colour in the diamond, the rarest being in the 'colourless' D-F range. The closer along the scale you get towards Z, the more yellow is in the diamond.
With only the naked eye, it can be difficult to make out the difference between a diamond in the D-F colourless range and the G-J near colourless range, particularly after the diamond has been set within the ring.
The above sketch illustrates how light returns is reflected and returned based on the cut of the diamond.
Clarity corresponds to the purity of a diamond. Most diamonds have tiny "birthmarks" known as inclusions. A diamond that has minimal inclusions and surface blemishes are rare and more valuable. This is because the smaller and fewer the inclusions, the more light can pass through the diamond, which contributes to its rare beauty.
The above diagram illustrates the clarity scale of a diamond.
A gemologist classifies a diamond using a magnification level of 10 times the naked eye. Diamond clarity ratings are based on the type, position, size and number of inclusions in the diamond. Flawless and Internally Flawless diamonds are the most rare and therefore the most expensive with a clarity rating of FL or IF.
A diamond’s weigh is measured in Carats and points. One carat equals one hundred points ( 0.01 carat = l point ). One carat is equal to 0.20 grams.
The higher the carat weight the more expensive the diamond. Half and full carat diamonds go up in because of their demand. The Carat Weight of a diamond refers to the actual weight of the stone. So therefore, Carat also corresponds to the size of the diamond, as the larger the diamond is, the heavier it is.
The above diagram illustrates diamond carat weight.