Various characteristics of diamonds are graded and categorized by the diamond industry. Learning about diamonds is first learning about the "four Cs" of diamonds which are considered the most important grades and categories:

Cut

Clarity

Color

Carat weight

These are the criteria jewelers use when grading diamonds, and they're the ones you'll need to understand to buy the right diamond for you. And then there's the "Fifth C":

Certificates

Cut

Cut is probably the most important, and most challenging, of the four Cs to understand. The brilliance of a diamond depends heavily on its cut.

Clarity

Most diamonds contain some inner flaws, or inclusions that occur during the formation process. The visibility, number and size of these inclusions determine what is called the clarity of a diamond. Diamonds that are clear create more brilliance, and thus are more highly prized, and priced.

Color

Colorless diamonds are the most desirable since they allow the most refraction of light (sparkle). Off-white diamonds absorb light, inhibiting brilliance.

Carat Weight

A carat is the unit of weight by which a diamond is measured. Because large diamonds are found less commonly than small diamonds, the price of a diamond rises exponentionaly to its size. Read a guide to get a better understanding of what a carat is and how it affects the appearance of a diamond.

The Fifth C: Certificates

The diamond certificate, which is sometimes called a grading report, is a complete evaluation of your diamond that has been performed by a qualified professional with the help of special gemological instruments. Each stone bears its own recognizable, individual characteristics, which is listed on the certificate.