How are diamonds sized?

How are diamonds sized?

John Cordova (Vice President of Human Resources, Robbins Bros.) gives expert video advice on: What is a diamond?; Why are diamonds so special?; What's the best advice for a couple buying an engagement ring? and more...

Diamonds are sized by carat weight. The carat weight is an actual weight on a scale. One carat is equal to one fifth of one gram. However, diamonds are also sized based on millimetre. Sometimes, you can get a diamond that weighs one carat that looks bigger or looks smaller. It's based on the preference of the guest.