Help & Advice Choosing your Diamond
C4. Carat Weight
The carat is the unit of weight for diamonds. The name
is derived from the seeds of the carob bean, which are
very uniform in weight and were used by early traders
as the universal measure for the stone.
In the early part of the twentieth century the carat
became standardised to the metric weight of 0.02g.
As most diamonds are considerably smaller than a carat, the measurement is divided
into 100 points:
one carat = 100 points
half a carat = 50 points
quarter of a carat = 25 points
...and so on.
These measurements are written as follows : - !ct, 0.50ct, 0.25ct.
The weight of any loose diamond is easy to obtain, but the weight of a diamond that is set into a piece of jewellery can only be estimated by the use of specialist gauges. These measure the diameter squared x the depth x 0.0061. An adjustment then has to be estimated based on how close the gem is to ideal proportions.
As the chart shows, there is a correlation between the weight of a diamond and its’ visual size. However, the correlation only applies to those diamonds that have those “ideal proportions” that we looked at in the first section on cut.
The value of a diamond is calculated on all of the characteristics we have looked at so far – cut, clarity, colour and finally carat weight – but nature being what it is, the raw diamond crystal with which we began is seldom perfect in all of these factors.
When the cutter begins his task he will be aiming to produce a polished gem of the maximum clarity and the greatest weight, whilst at the same time always endeavouring to make it as bright and sparkly as possible. In the diagram below the proportions are exaggerated to demonstrate the principle. In each case the diameter of the gem is the same, so looked at from above they will appear the same size. However, because of the other proportions, each gem will obviously have a very different weight.
In pure terms, the one on the left of our diagram will weigh about half as much as the one on the right. In terms of value, however, the biggest is not the best. As you can see from the next row of diagrams, the detour from “ideal proportions” the cutter has had to make to achieve the best yield from the rough affects the way the diamond will sparkle and it is the gem in the middle that will fetch the highest price as its’ proportions best capture the light.
In reality, these variations are not discernable except to an expert, but they are essential for us to know when placing a value on an individual diamond.
C5. Confidence
Buying diamonds is always an exciting event and often a very emotional one. The significance of diamonds in our society is that of a powerful symbol of love and a promise that means forever.
Diamonds can also be a status symbol or a fashion statement, but whatever your motivation to buy, you need to feel that the piece of diamond jewellery you choose fulfils all your desires.
In this book we have tried to give you an insight into how diamonds were formed, recovered and then fashioned into scintillating gems. The final stage is to set them into precious metals such as gold or platinum to become the item of jewellery you will treasure.
Bringing all these things together is our job and our passion and we use our extensive knowledge of diamonds and precious metals to bring you the very best we can in terms of craftsmanship, quality and style.
The ranges we have to offer have been carefully chosen and we can trace our supply chain right back to the source. We also subscribe to the Kimberley Agreement, so ensuring that all our diamonds are ethically produced.
We are happy to put all of our expertise at your disposal and we will be glad to answer any of the questions you may have, so that you can buy with confidence.
Picketts & Pursers
