Three Ways to Judge Diamond Quality – Know You’re Buying the Best Diamond

Buying any diamond is an important investment that should never be taken lightly. When you begin to research the ways of judging diamond quality, it is easy to become confused. Because diamonds are graded according to color and clarity, and differ in cut, it is sometimes hard to understand the jeweler speak when you are shopping for diamonds. Do you want a VVSI2 D diamond or an SI1 G diamond… and what on earth is the difference?

You have probably heard that diamonds are measured by four C’s: Carat, Color, Clarity, and Cut. The Carat refers to the size. This is easy to understand: a larger diamond is worth more than the same quality diamond in a smaller size. In order to know that you are buying the best diamond for your money, it is worth your time to understand more about the other 3 C’s.


Diamonds range in color from truly colorless to white to yellow to even yellowish brown. The gradings start at D, and range all the way to Z. Diamonds graded D, E, and F are truly colorless and considered the highest quality, D being the very best. Gradings G,H,I, and J are described as “white,” and are nearly colorless. Beginning with the grading K, and progressing to Z, diamonds are tinted. K,L, and M diamonds are just barely tinted and are said to “set white.” This means that if set in yellow gold, these diamonds will appear to be white, although the tinting might be noticeable if this grade of stone were set into white gold. As the grades progress further through the alphabet, the diamonds become more tinted and go down in value. Exceptions to this are in the later grades near the end of the alphabet. These diamonds are so strongly tinted that they become known as “fancy” colored diamonds and the value of these colored diamonds is higher than those in the middle of the color range. It can cost upwards of $100 to properly grade a diamond for quality, so it is now customary for many stones smaller than a carat to be instead graded in a range. So your jeweler might tell you a particular diamond is graded GH, for example.


The clarity grading scale is where most folks get confused when it comes to diamonds. But this is easy to understand once you realize that the rankings on this scale are based on three letters, standing for easily understood words. The most important to understand is I, which stands for Inclusion. An inclusion is a mineral or fracture, or anything that would interfere with the free passage of light through the gem. Other letters included in the grading scale for diamond clarity are V and S, which simply stand for very and small. So a VVSI diamond would have a very, very small inclusion, for instance. Clarity can further be noted by including a number behind these letters. A VVSI1 diamond would be less included than a VVSI2. The highest clarity grade is “flawless,” but diamonds graded all the way down to SI2 will not show inclusions to the naked eye. Ask the jeweler to let you see the stones through the jeweler’s loupe and you will be able to see the inclusions in your stone. I1 and I2 graded diamonds will have inclusions visible to the unaided eye.


The cut of a diamond is not graded, and this can be the hardest property to judge. A diamond’s brilliance or “fire,” which is it’s ability to refract light, is mostly determined by its cut. The cut facets of the stone act as mirrors and reflect the light back at the observer. This works best when the facets are cut at the precise angle of 41 degrees. This is easy to do on a perfectly proportioned stone, but mined diamonds can be irregularly shaped. Achieving this perfect angle is sometimes impossible without sacrificing large chunks of the stone, reducing the carat weight dramatically. So some stones will be more valuable when cut at less than exactly 41 degrees, according to weight. A diamond’s cut can be as variable a factor as the color and clarity.

All these qualities combine in various ways to produce stunningly wide arrays of choices in diamond selection. Understanding the differences in grades will help you to know that you are buying the best diamond for your money when you shop for that special stone.

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