Every Diamond is a miracle of nature, and like snowflakes, no two are the same. Only from the middle of the twentieth century has there been a standard by which diamonds could be judged. This standard was first created by the Gemological Inistitute of America (GIA), and is now the globally accepted standard for describing a diamond's Colour, Clarity, Cut and Carat Weight. Today, what is known as the 4 C's of diamond quality is the universal method for assessing the quality of a diamond anywhere in the world. This now also means that diamond customers can know exactly what they are about to purchase.
A rough diamond can be cut into a large amount of shapes, the most popular being the Round Brilliant and Princess cuts. A diamond's shape is sometimes determined by the rough stone's original shape and size, best determining which cut should suit the final diamond. Many of the higher carat diamonds are shaped into fancy cuts such as the Pear, Oval and Cushion shapes.
Diamonds are colour graded against a series of "colour masterstones". The diamond colour evaluation is actually based on the absence of colour, with a chemically pure and structurally perfect diamond being almost like a drop of pure water. These diamonds are of the highest value.
The clarity scale reflects a diamond's characteristics. Mostly not visible to the naked eye, the visibility of inclusions are perceived as flaws within the diamond. Diamonds are thus rated on the visibility, size, location and amount of inclusions it may contain. The less inclusions a diamond contains, the higher it will be rated on the clarity scale. Many inclusions and blemishes are too tiny to be seen by anyone other than a trained diamond grader, and so although to the naked eye a VS1 and SI2 diamond may look exactly the same, these diamonds are quite different in terms of their overall quality.
A diamond's cut is crucial to the stone's final beauty and value, and is the most complex and technically difficult to analyse of the 4 C's. A diamond's cut grade is really about how well a diamond's facets interact with light, resulting in what we generally think of as "sparkle". When a diamond is cut with the proper proportions, light is returned out of the top of the diamond. If it is cut too shallow, light leaks out of the bottom, and if too deep it escapes out of the side
Diamond Carat Weight
A carat is the measurement by which a diamond is weighed. A metric "carat" is defined as 200 milligrams, and each carat can be subdivided into 100 points. All else being equal, diamond prices increase with larger diamonds as they are more rare and desirable. Two diamonds of equal carat weight however can have very different values depending on their clarity, colour and cut.