What does it mean?
When we read encyclopaedias or watch documentaries about diamonds, we always hear about large specimens of several hundred carats being removed from the earth. Now it may sound terribly exciting, but what is a carat? Not many people know. If the time comes that you have to buy a diamond, it becomes even more important since carat can have a large effect on the price of a diamond.
The word carat comes from the carob seeds that were used in ancient times as a means of standardised weighing. Originally used mainly for gold or other precious metals, it was soon used for gems as well. The carob seed was used because of its, generally, uniform weight. Although studies recently discovered that carob seeds tend to differ in weight as much as normal seeds, it is true that with these seeds it is easier to pick out small or large ones from the general assortment – making the system easier to standardise.
A carob seed weighs about 195 grams or so and today the official weight of one carat is 200 milligrams. The carat is further divided into 100 points for finer carat weight detail. That means a diamond of 0.50 carats would weigh about 100 milligrams and be worth ½ a carat.
It must be mentioned that while carat is a measure of the weight of a diamond, it does not necessarily scale upwards. Larger diamonds are rarer and, therefore, more valuable. Two 0.50 carat diamonds are not worth as much as a single 1 carat diamond (assuming they have the same cut, clarity and colour) simply because 1 carat diamonds are rarer than two 0.50 carat diamonds.
Another thing to remember is that the price of diamonds in regard to carats does not scale linearly. The price tends to jump between different carat values with smaller carats sometimes being worth more than larger carats (especially in the points ranges). Again, rarity plays a role as some carats are just more common or uncommon than others. People, however, also play a role since the demand for certain carats are higher than others and can affect the price considerably.
To ensure that all diamond sellers and jewellers try to work from the same baseline price, the Rapaport Diamond Report is published weekly by Martin Rapaport. This report shows the current price trends in diamonds throughout the world in regard to clarity, cut, colour and weight. Many jewellers and sellers use this report as a baseline for their pricing.
But is a high carat diamond necessarily a large diamond? For the larger carats there is definite difference in size. The difference between a 5 carat and a 10 carat diamond is rather obvious. Once you reach the smaller carats, where most shoppers find themselves, the difference becomes less obvious. The cut of a diamond can have an effect on the visual size of a diamond. In other words, a diamond of a small carat may appear large due to its cut and a diamond of a large carat may appear smaller than it is.
The difference is especially hard to see once the diamond has been set, but may be visible – with some effort – before it is set.
Carat is one of the factors that determine price. A smaller carat diamond with a good clarity and colour with an appropriate cut may be more beautiful than a larger carat with only average clarity, colour and cut.
When buying diamonds, carat is one of the few things that you, as the buyer, actually have some control over. Clarity and colour are determined by nature and the cut is determined by the gem cutter before it reaches the jeweller (although there are instances where the buyer can determine the cut, but that costs extra). You know what size you want and, more importantly, how much you have to spend.
Just remember that bigger is not always better – just more expensive. At least when it comes to diamonds.
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