About the 4 C’s of Diamonds: Carat, Color Clarity, and Cut

Diamonds – The 4 C’s

Buying a diamond is an important decision that will last a lifetime – and often many generations beyond. For the average consumer, the diamond trade can be complicated and confusing, for there are many aspects to keep in mind when selecting the perfect piece for your needs. The “4 C’s” is a quick mental guide that can help you ask the right questions and buy with confidence, and includes the fundamental categories of assessing the value of a diamond – carat, color, clarity, and cut.


A carat is the metric weight used for diamonds and all gemstones. This measurement is the most objective of the “4 C’s,” in that it is a quantitative measurement and cannot be subjected to interpretation. One carat is equal to 0.2 grams, and often carats are divided into 100 point increments to increase precision. For example, a piece that is 1/2 a carat would be 50 points.

Carat Table for Diamonds

Even small variations within the weight of the piece will translate to significant differences in price, and often carats are rounded to the nearest common fraction, meaning a half carat diamond could be anywhere from 45 to 55 points. With this in mind, it is important to find the most precise measurement available. Weight is only one aspect to consider, however, and must be informed by three other important characteristics before making a purchase.


Often hard to gauge by comparing diamonds from store to store, color is an important factor in determining the value of a particular stone. Diamonds are more valuable the less color they have, as many stones often have a yellow or brownish tint which subdues the stone’s famous brilliance. The lack of color is most desirable in diamonds because the prism effect and play of colors that result is observed best with white light. Color was traditionally graded with a range of categorizations delineated by letters, numbers, and even Roman numerals. With all of these conflicting grading systems, it was relatively difficult to get an accurate sense of how stones related to one another, and inaccuracies and inconsistencies were common.

Diamond Color Scale (Letters Meaning)

To provide a more precise system of measuring color, the Gemological Institute of America developed a universal grading system using letters. Starting with grade D, which denotes absence of any body tint, the scale continues down through the alphabet. Stones remain indistinguishably clear through letter H or so. Around letter J, a slight yellowish tint becomes visible, and continues to intensify through letter Z, while grades below are reserved for heavily colored blue, red, and pink stones called “fancycolored.”

It is very rare to find a diamond with a grade D for color. The lower the grade, the less brilliant a diamond will appear as less of the light spectrum will be broken up inside the stone itself. As a general rule, a grade of H is considered very good, and only a small percentage of stones exhibit this degree of colorlessness.

It is important to investigate who has performed grading on the stones themselves, as opinion and qualifications are variables that can substantially affect the outcome. While many retailers carefully guard their reputation and would never intentionally mislead customers, it is important nonetheless to follow up with who performed the initial grading.


Another major determining factor in the value of the diamond is clarity, or the absence of inclusions. The majority of pieces contain small flaws either on the surface or within the crystal structure itself. These can include surface blemishes, spots of carbon, internal feather cracks, and others that may disrupt the optical quality in the stone.

Diamond Clarity Scale

To help establish a universal, more objective grading system, again the Gemological Institute of America developed a categorization method for grading the clarity of diamond samples. Using a 10 power magnification, the scale describes any visible inclusions. A stone without any such aberrations is considered an F1 on the scale, or flawless. Such pieces are incredibly rare. The next stages, VVS1-VVS2, describe pieces with very very slight inclusions, minute enough to barely be visible even under 10 fold magnification. VS1-VS2, the next two categories, very slight inclusions, are only a little more visible, but still fairly difficult to locate. In the S1-S2 categories, these flaws become more noticeable by trained appraisers, but still remain invisible to the naked eye. I1-I3 are for pieces whose flaws are more noticeable, even when approaching unaided vision.

Since classifications can differ by the appraiser, often it is desirable to obtain a thirdparty appraisal from certified gemstone labs. These can cost upwards of $100, however, and that cost must be born by the consumer. It is also better to have a single appraiser evaluate several stones, to maintain consistency in the inevitable biases and idiosyncrasies that this classification system allows.

Some minor inclusions can give a particular piece some unique character, and thus not all flaws necessarily degrade a given piece. Practice, and a handy magnifier, can allow almost anyone to give diamonds a general assessment in-store.


Arguably the most important yet overlooked factor in the brilliance of a diamond is the cut. A diamond that is skillfully cut will refract nearly 100 percent of the light entering its surface back up through the crystal structure, creating beautiful interplays and the characteristic diamond luster. Sometimes, the carat of a particular piece must be partially sacrificed to attain the full potential of the stone, as precise cuts redirect light back to the viewable surface.

Diamond Cut Chart

Traditionally, there are 58 facets in a cut of a round diamond, each as small as two millimeters in diameter. The precision of these cuts affect the three main attributes of a diamond’s appearance, which are brilliance (total reflected light), scintillation (sparkle), and fire (spectrum of colors visible). The size and symmetry of these cuts, as well as the final polish, will determine the overall effect in each category.

As with other qualities like clarity and color, there is a fair amount of interpretation and ambiguity as to what makes an ideal cut. Gemologists have somewhat reached consensus upon a scale of values that make up the most effective cuts, but it is also important to gauge the shine and liveliness of a particular piece first hand. Along with the other three characteristics of carat, color, and clarity, strong emphasis should be placed on the quality of a diamond’s cut when considering a piece for purchase. Keeping the 4 C’s in mind will help you make the best selection possible for this remarkable gemstone.