There are four factors that determine the value of a diamond, collectively known as the 4Cs of Diamonds. The best way to shop for a diamond is to have a good understanding of the 4Cs and determine which factors are most important to you, as each “C” means something different for each individual. For example, some women care most about the carat weight and diamond size, while others might consider the clarity and cut more important. A diamond jewelry purchase should never be based on the specifications alone.
 
A jeweler is your best source of information, but review each page dedicated to the 4Cs of diamonds to learn what you should look for when searching for your next diamond jewelry purchase -- whether online or at jewelry stores near you. Here's a handy guide to the Diamond 4Cs charts (pdf) to bring with you as you shop.

Diamond Carat Weight

Carat weight measures a diamond’s weight and size. Because large diamonds are rare, they generally have a greater value per carat.
Learn about diamond carat weight >

Diamond Clarity

A diamond’s clarity is affected by any external and internal characteristics created by nature when the diamond was formed or as a result of the cutting process. Learn more about diamond clarity and see diamond clarity charts in this section.
Learn about diamond clarity >

Diamond Color

While the most popular diamonds are colorless, diamonds come in every color of the spectrum. Diamond color grades are determined by professionals under ideal circumstances, a situation seldom duplicated outside of a laboratory. Choose a diamond based on its appeal to you, rather than on a technical color scale.
Learn about diamond color >

Diamond Cut

Each diamond is cut to very exacting standards. The cut is one of the most important quality factors of a diamond, as it affects the diamond’s optical and physical properties, like brilliance – how a diamond reflects light.
Learn about diamond cut >