When choosing your diamond, you need to consider the “Four C’s”.
Perhaps the most important and least understood of the 4Cs as it is the cut which gives a diamond the sparkle and brilliance we all look for. A diamond cutter must observe strict geometric proportions when he puts on the facets so as to maximise a diamond’s natural reflective and refractive properties. A poorly cut diamond will lack fire and brilliance and seem dull and lifeless by comparison to a well cut stone.
The rarest & most valuable white diamonds are colourless, but most contain a slight hint of colour. They are graded starting from “D” (colourless) right down to Z. The difference between one grade to the next is very subtle. Sometimes diamonds occur in a pure colour such as pink, blue or green. Naturally coloured diamonds are rare and extremely valuable and are known as “fancies”. Treated coloured diamonds are much less expensive.
Most diamonds contain natural inclusions, sometimes called nature’s fingerprints. These can vary from tiny black spots to bubbles or internal fractures. The number, size and location of any of these can affect the passage of light through the diamond and will affect the value of the stone. Flawless or internally flawless diamonds are rare, but generally very minor inclusions, visible only through a 10X jewellers loupe, will not compromise the diamond’s beauty. Diamonds are graded from flawless down to P3 at which point the inclusions are likely to be obvious to the naked eye.
The size of a diamond is measured in carat-weight, each carat being divisible into 100 “points” so that 50 points is 0.50ct. As larger diamonds are rarer, this affects the price per carat and a single 1 carat stone will be worth more than double two smaller diamonds of the same quality. Bigger is not always better, however, and a smaller, perfectly cut, flawless, white diamond will always command a higher price than a poorly cut, tinted and included stone.