Monday, August 1, 2011
It is important to know what you are getting when buying diamonds for your wedding ring. The price of your diamond will depend on the stone’s carat, colour, clarity and cut.
Diamonds and precious stones are measured by their mass, not their size. The word ‘carat’ comes from the historical method of weighing things by carob seeds. One carat was equivalent to one carob seed, which was the standard ancient weight measurement. Standardisation now means one carat is equivalent to one fifth of a gram. One carat is divided into 100 points so 25 points is a quarter of a carat.
Diamonds can cover the entire spectrum of colours including pink, blue and green and red but most are a faint yellowish colour. The most valuable diamonds are colourless, which are very rare, followed closely by pink or blue stones.
The Gemological Institute of America established a grading scale of colour starting with D, for colourless and most highly prized, through to Z for the least desirable yellow-brown stones. Diamonds graded D to F are the most valuable and most stockists carry F or G diamonds.
Most diamonds contain ‘inclusions’ – tiny traces of non-crystallised carbon, which occur during the formation process. The clarity of a diamond is determined by the degree to which it is free from inclusions. A diamond’s value is determined by its ability to transmit light so the clearer the stone the better. Diamonds with the smallest amount of inclusions are the most rare and expensive.
The scale of measurement for determining a diamond’s clarity is the GIA index. It ranges from ‘imperfect three’ for diamonds with a lot of inclusions to flawless for those with no inclusions visible to the naked eye. The highest grade of diamond carried by most jewellers is VS – meaning they have a very small number of inclusions. Flawless diamonds are extremely rare and expensive.
The cut of a diamond is considered the most important factor of the Four C system in terms of the stone’s appearance and overall value. The cut does not refer to the outward form of a diamond and is probably most easily understood as its symmetry and proportions.
The diamond cutter’s expertise lies in being able to release the maximum amount of sparkle from a rough diamond. Cut is the only one of the Four C’s that can be manipulated by humans and the cutter’s degree of skill has an enormous impact on a stone’s appearance. A good cutter can make an otherwise average stone appear a lot more valuable.
There are different styles of cut including: brilliant, princess, oval, emerald, marquise or pear shapes. The idea is to create a diamond that will reflect the most light and emit the biggest sparkle.