HOW TO BUY DIAMONDS
It is easy to weigh an unmounted diamond, but once it is in a setting, it is only possible to estimate its weight by using special gauges and formulae.
WHAT IS A CARAT?
The carat is a unit of weight that is derived from the carob seed. The pods of the carob, or locust tree, contain tiny seeds which are remarkably consistent in weight. These seeds were used by early gem traders to weigh their diamonds.