Carat is a measure of a diamond's weight and not its size. The word carat derives from ancient times when gems were measured using the weight of a carob seed.

"In ancient times, diamonds were measured using the weight of a carob seed"

One carat equals one fifth of a gram. It can also be divided into 100 'points' so, a half carat diamond is the same as a 50 point or a 0.50 carat diamond.

Larger weight diamonds are rarer and are more valuable. However, two diamonds of the same can have very unequal values, depending on their clarity, colour and cut.

A good cut and certain mounts can make a diamond appear larger than its actual carat weight so it's worth taking your time to find the right diamond and a setting that optimises its beauty