Carat, Clarity, Colour & Carat
The size and weight of diamonds is measured in carets. Large diamonds are more valuable and desirable because they are rare – and because the cut, colour and brilliance of diamonds are most evident in larger stones. As less than 1 in 20 diamonds are one caret or more, you will perhaps hear of their size being referred to as so many 'points'. One caret = 100 points. So a 10 point diamond is a tenth of a caret. The value of a diamond will not solely be determined by its size and weight. Other factors will be adjudged, such as the clarity, cut and colour of the stone.
The clarity of a diamond affects its brilliance and its value. When diamonds are formed they often contain tiny imperfections both externally and internally. External flaws are called 'blemishes' and internal imperfections are known as 'inclusions'. Jewellers grade diamonds according to their clarity. Many flaws are invisible to the naked eye, only detectable by viewing the stone through a magnifying instrument.
Flawless diamonds are extremely rare and highly valued. Blemishes and inclusions interfere with light passing through diamonds, and the less flaws there are, the less effect there will be on the stone's sparkle and brilliance.
Diamonds can be treated to improve their clarity. Lasering is a treatment in which imperfections are removed by drilling into the stone using laser technology to treat inclusions. A less permanent and somewhat controversial treatment is called Clarity Enhancing. This method involves injecting material into a diamond to temporarily enhance its clarity.
The value and rarity of diamonds is affected by their colour or tint. Jewellers grade diamonds on an alphabetic scale from 'D' (colourless) to 'Z' (tinted yellow). Those graded at the 'colourless' end of the scale are the most highly valued. Also highly valued are diamonds strongly tinted with a particular pure colour.
Each and every diamond is unique, with its unique colours, sparkle, brilliance and personality. So each stone should be judged on an individual basis. A particular tint may well bring out something special in a diamond, depending on other factors such as the cut of the stone and it's clarity.
Diamonds are cut by expert craftsmen. How a stone is cut can greatly affect its sparkle, brilliance and value.
Diamonds can be cut in several shapes, but it is the quality of the cut that is vitally important. Stones that are undercut or cut too deeply will not have the brilliance or sparkle than those cut at a better angle and in better proportion .
Poorly cut diamonds will lose light as it passes through the stone. A better cut will allow the light to pass through the diamond and reflect in straight lines, unhindered and the more brilliant for it.