The document outlines the 4Cs of diamonds—cut, clarity, color, and carat—developed by the GIA to enable objective grading. It details how each factor influences the quality and value of diamonds, including categories ranging from ideal to poor cuts, as well as clarity ratings from flawless to included. It emphasizes the importance of these attributes in assessing diamond quality and the considerations for potential buyers.

1. The 4c’s of a Diamond Because diamonds are so valuable, it’s essential to have a universal grading system for comparing their quality. In the 1940s and ’50s, GIA developed the 4Cs and the GIA International Diamond Grading System™ to objectively compare and evaluate diamonds.

2. Cut A well cut diamond will have an amazing brilliance and fire. This is caused by white light reflecting off the diamond’s surfaces and the mirrored depths of the pavilion. The key to desirable fire and brilliance is proportion. Light striking a shallow cut diamond will fall out the other side and not reflect back to the top. Light striking a deep cut diamond will get lost in the pavilion and also be unable to reflect back to the top Ideal cut: Represents roughly the top 3% of diamond quality based on cut. Reflects nearly all light that enters the diamond. An exquisite and rare cut. Very good cut: Represents roughly the top 15% of diamond quality based on cut. Reflects nearly as much light as the ideal cut, but for a lower price. Good cut: Represents roughly the top 25% of diamond quality based on cut. Reflects most light that enters. Much less expensive than a very good cut. Fair cut: Represents roughly the top 35% of diamond quality based on cut. Still a quality diamond, but a fair cut will not be as brilliant as a good cut. Poor cut: Diamonds that are generally so deep and narrow or shallow and wide that they lose most of the light out the sides and bottom. Blue Nile does not carry diamonds with cut grades of poor.

3. Clarity All diamonds have identifying characteristics, but most are invisible to the naked eye. To view a diamond, experts use a 10x magnifying loupe which allows them to see the appearance of tiny crystals, feathers or clouds. These natural phenomena are called inclusions. There are five categories in class that anyone interested in purchasing a diamond should be aware of when grading clarity. Fl, IF Flawless, Internally Flawless: No internal or external imperfections. Internally Flawless: No internal imperfections. Very rare. VVS1, VVS2 Very, Very Slightly Included: Very difficult to see imperfections under 10x magnification. An excellent quality diamond. VS1, VS2 Very Slightly Included: Imperfections are not typically visible to the unaided eye. Less expensive than the VVS1 or VVS2 grades. SI1, SI2 Slightly Included: Imperfections are visible under 10x magnification, and may be visible with the unaided eye. A good diamond value. I1, I2, I3 Included:

4. Color Many experts name color as the number one consideration in choosing a diamond. A diamond's color is graded on an alphabetical scale from D-Z, with D being absolutely colorless and Z being light yellow. Beyond "Z", a diamond is considered to be an exotic or "Fancy" color. Since color differences can be so subtle, they are impossible to determine by the untrained eye. To grade a diamond, gemologists often place it on a white background next to another diamond that has been previously graded. If all other factors are equal, the less color in a diamond or the higher color rating, the more valuable a diamond becomes. Likewise, as the amount of color increases, the price of a diamond decreases (though this does not necessarily reduce the beauty of a diamond.) What Color is Right for Me? For the purist, look for a colorless diamond with a grade of D-F for a diamond with no discernible color. For an excellent value in a diamond with little or no noticeable color to the unaided eye, look for a near-colorless grade of G-I

5. Carat Key Points Carat is specifically a measure of a diamond's weight, and by itself may not accurately reflect a diamond's size. We tend to evaluate diamond size by viewing it from the top because that is how diamonds are presented to us when set into a ring. To understand diamond size, carat weight should be considered in conjunction with two other criteria: Diamonds and other gemstones are weighed in metric carats: one carat is equal to 0.2 grams, about the same weight as a paperclip. (Don’t confuse carat with karat, as in “18K gold,” which refers to gold purity.) Just as a dollar is divided into 100 pennies, a carat is divided into 100 points. For example, a 50-point diamond weighs 0.50 carats. But two diamonds of equal weight can have very different values depending on the other members of the Four C’s: clarity, color and cut. The majority of diamonds used in fine jewelry weigh one carat or less.