The carat weight of your diamond

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 : - 0.75ct, 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.