How Diamonds Are Graded

You walk into a jewelry store ready to buy a diamond—whether it’s an engagement ring or a statement piece dripping in brilliance. Every diamond sparkles, every stone looks stunning… so how do you choose the right one?

The answer lies in diamond grading. Understanding how diamonds are evaluated will help you shop with confidence and get the best value for your investment.

The Four C’s of Diamond Grading

Gemologists use an internationally recognized system known as the Four C’s to evaluate diamonds. These criteria measure a diamond’s quality and overall value:

• Color

• Clarity

• Carat Weight

• Cut

Let’s take a closer look at each one.

Diamond Color

For white diamonds, less color means higher value. While diamonds may appear white to the untrained eye, most contain subtle yellow or brown tones.

Color is graded on a scale from D to Z:

• D–F: Colorless (highest value)

• G–J: Near colorless

• K–M: Faint yellow

• N–R: Very light yellow

• S–Z: Light yellow

Gemologists compare each diamond to master stones under controlled lighting to determine its color grade. The more colorless the diamond, the rarer—and more expensive—it is.

Tip: Near-colorless diamonds (G–J) often offer excellent value and still appear bright white, especially once set in jewelry.

Diamond Clarity

Clarity refers to the presence of inclusions (internal flaws) and blemishes (surface imperfections). The fewer imperfections a diamond has, the higher its clarity grade.

Clarity is assessed using magnification and graded as follows:

• FL: Flawless

• IF: Internally flawless

• VVS: Very, very slightly included

• VS: Very slightly included

• SI: Slightly included

• I: Included

Many inclusions are invisible to the naked eye, especially in smaller diamonds. That means you don’t always need a flawless diamond to get a beautiful one.

Diamond Cut

Cut is often considered the most important of the Four C’s because it directly affects how much a diamond sparkles.

A well-cut diamond reflects light brilliantly, while a poorly cut one can look dull—even if it has excellent color and clarity.

Cut quality is graded as:

• Excellent

• Very Good

• Good

• Fair

• Poor

Gemologists evaluate a diamond’s proportions, symmetry, and polish to determine how effectively it reflects light. A superior cut can dramatically increase a diamond’s beauty and value.

Carat Weight: Size and Rarity

Carat refers to a diamond’s weight, not its size. One carat equals 0.2 grams (200 milligrams).

As carat weight increases, diamonds become exponentially rarer, which is why prices rise sharply with size. A 1-carat diamond is significantly more valuable than two half-carat diamonds of the same quality.

Remember: Bigger isn’t always better—balance carat weight with cut quality for maximum brilliance.

Final Thoughts

Diamond grading is both a science and an art, performed by skilled gemologists using precise standards. Understanding the Four C’s empowers you to choose a diamond that fits your style, budget, and expectations.

Armed with this knowledge, you’ll shop smarter—and appreciate just how much expertise goes into every diamond you see.