The 4C's of Diamond Quality

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The 4C's of Diamond Quality

Jewelry professionals use a systematic way to evaluate and discuss the factors involving the quality of a diamond. Otherwise, there would be no way to compare one diamond to another. And there would be no way to evaluate and discuss the qualities of an individual diamond.

Diamond professionals use the grading system developed by GIA in the 1950s, which established the use of four important factors to describe and classify diamonds: Clarity, Color, Cut, and Carat Weight. These are known as the 4Cs. When used together, they describe the quality of a finished diamond. The value of a finished diamond is based on this combination. 


diamond quality chart 


Diamond Color Actually Means Lack of Color

diamond color

Understanding what diamond color means helps in choosing the right diamond. Interestingly, the diamond color evaluation of most gem-quality diamonds is based on the absence of color. Diamond color is the hue of a diamond based on the GIA diamond color scale, which grades the diamond’s color on a spectrum of D (colorless) to Z (light yellow hue). The absence of color is what determines both its grade and value, as well as has a significant impact on its appearance. Diamond color grade is typically determined with the diamond face down and the culet facing up against a pure white surface, following a grading scale of D (colorless) to Z (faint yellow).

Many of these diamond color distinctions are so subtle that they are invisible to the untrained eye; however, these distinctions make a very big difference in diamond quality and price. Hence, it is important to get a GIA expert’s opinion in evaluating the best color for your diamond. 


The GIA D-to-Z scale is the industry standard for color-grading diamonds. Each letter represents a range of color based on a diamond’s tone and saturation.  
diamond color scale 


COLORLESS DIAMONDS: The rarest and highest quality with a pure icy look.
  • D-F Color Diamonds

NEAR-COLORLESS DIAMONDS: No discernible color; great value for the quality.
  • G-H Color Diamonds
  • I-J Color Diamonds
FAINT COLOR DIAMONDS: Budget-friendly pick; pairs nicely with yellow gold.
  • K Color Diamonds

** Helpful Hint ** Diamond prices decline or increase in alphabetical order. For example, a diamond with a G color grade is less expensive than a diamond with a D color grade.


Subtle differences in color can dramatically af­fect diamond value. Two diamonds of the same clarity, weight, and cut can differ in value based on color alone. Even the slightest hint of color can make a dramatic difference in value.

Diamonds come in many colors. Diamonds that range from colorless to light yellow and brown fall within the normal color range. Within that range, colorless diamonds are the most rare, so they’re the most valuable. They set the standard for grading and pricing other diamonds in the normal color range.

At the GIA Laboratory, diamonds are color graded under controlled conditions by comparing them to round brilliant diamonds of known color, called masterstones.

Many diamonds emit a visible light called fluorescence when they’re exposed to ultraviolet (UV) radiation. Although invisible to the human eye, UV radiation is everywhere. Sunlight contains it. Fluorescent lights emit it, too. Under the right conditions, you can see fluorescence in about 35 percent of gem diamonds.

Blue is the most common fluorescent color in gem-quality diamonds. In rare instances, fluorescence can be white, yellow, orange, or many other colors.

Strong blue fluorescence can make a light yellow diamond look closer to colorless in sunlight. Blue and yellow are color opposites and tend to cancel each other out, so blue fluorescence masks the yellow color. If the fluorescence is too strong it can make the stone look cloudy or “oily,” which can lower the value of the diamond.


Diamond Clarity Refers to the Absence of Inclusions and Blemishes

diamond clarity
To understand diamond clarity, we must first understand how diamonds are created. Natural diamonds are the result of carbon exposed to tremendous heat and pressure deep in the earth. This process can result in a variety of internal characteristics called ‘inclusions’ and external characteristics called ‘blemishes.’
In most cases, a diamond’s beauty is not affected by these in any way since most inclusions can’t be seen with the naked eye. When referring to inclusions, gemologists often use the term “internal characteristics” instead of flaws. Internal characteristics are what give a natural diamond its character. It’s also important to note that diamonds with the fewest and smallest inclusions receive the highest clarity grades—and higher price tags to reflect that.
Evaluating diamond clarity involves determining the number, size, relief, nature, and position of these characteristics, as well as how these affect the overall appearance of the stone. If you are trying to determine what is the best clarity for a diamond, remember that no diamond is perfectly pure. But the closer it comes to purity, the better its clarity. All diamonds are unique, not perfect. They are made underground through enormous pressure and heat. Natural inclusions and blemishes are inevitable.
Sometimes, one factor makes more difference to the clarity grade than the others. But it’s not always the same one. The relative importance of each factor varies from diamond to diamond. For example, an inclusion off to the side of a stone would have less impact on clarity than the same size inclusion located directly under the table. In this case, the position is probably the determining factor.
Occasionally, if an inclusion has the potential to cause damage to a stone, it can affect the grade. But this is rare, and usually applies only to Included (“I”) diamonds.
Clarity characteristics might have a negative influence on a diamond’s value, but they can have positive effects as well. For one thing, they help gemologists separate diamond from imitations. (This is easier with included diamonds than with flawless ones.) And because no two diamonds have exactly the same inclusions, they can help identify individual stones. They can also provide scientists with valuable information about how diamonds form.


The GIA clarity scale includes eleven diamond clarity grades. The scale narrows at the top because there are very few diamonds in the higher clarity grades.
gia clarity scale 
The GIA Diamond Clarity Scale has 6 categories, some of which are divided, for a total of 11 specific grades.
  • Flawless (FL) No inclusions and no blemishes visible under 10x magnification 
    • No internal or external characteristics
    • Less than 1% of all diamonds are FL clarity
    • A flawless diamond is incredibly rare because it’s nearly impossible to find a diamond 100% free of inclusions
  • Internally Flawless (IF) No inclusions visible under 10x magnification
    • Some small surface blemishes may be visible under a microscope on IF diamonds
    • IF diamonds have no inclusions within the stone, only surface characteristics set the grade
    • Visually eye clean
  • Very, Very Slightly Included (VVS1 and VVS2) Inclusions so slight they are difficult for a skilled grader to see under 10x magnification
    • VVS clarity is rare and results in an eye clean appearance
  • Very Slightly Included (VS1 and VS2) Inclusions are observed with effort under 10x magnification, but can be characterized as minor
    • Minor inclusions ranging from difficult (VS1) to somewhat easy (VS2) to see at 10x magnification
    • Great value; Devon's Diamonds & Decor's most popular diamond clarity
  • Slightly Included (SI1 and SI2) Inclusions are noticeable under 10x magnification
    • If eye clean, SI diamonds are often the best value
    • SI2 inclusions may be detectable to a keen unaided eye, especially when viewed from the side
  • Included (I1, I2, and I3) Inclusions are obvious under 10x magnification which may affect transparency and brilliance
    • Devon's Diamonds & Decor does not sell I clarity grade diamonds in their jewelry

Flawless Diamonds


“Flawless” diamonds are flawless inside and out. At 10X magnification under a microscope, they have no visible blemishes or inclusions. (If a diamond has inclusions too small to see at this magnification, they have no effect on the clarity grade).

“Internally flawless” means that the stone has blemishes but no inclusions. Blemishes encompass things like scratches and nicks that exist only on the external diamond surface. Usually, they can be polished away and likely won’t affect the clarity grade too much. On the other hand, inclusions like crystals and feathers (cracks) exist inside the stone. These have much more impact on the clarity grade.

Incredibly rare, flawless and internally flawless stones account for just 2% of gem-grade diamonds. Thus, they command high prices, especially in large carat sizes.

You’ll find an enormous price difference between an F and an IF stone, like that between an IF and a VVS stone. As clarity grades go down, the price differences decrease exponentially. 

Very Very Slightly Included (VVS) Diamonds


VVS stones have minute inclusions, so small they’re barely noticeable under 10X magnification. Most consumers likely can’t tell the difference between F, IF, and VVS diamonds.

Any stone in the VVS range still has extremely high clarity and will command a premium price.

Very Slightly Included Diamonds


VS stones occupy the upper-middle range of diamond clarity grades. They have minor inclusions, which means they don’t interfere much with clarity, even though they’re larger or more numerous than those in VVS stones.

Slightly Included Diamonds


Stones in the SI range drop into commercial-quality. The inclusions are noticeable at 10X magnification but most likely not with the naked eye. Still, an SI stone may appear cloudier and less brilliant, especially to someone familiar with fine jewelry.

Included Diamonds


Generally, buying I stones isn’t a good idea, even though they’re technically gem quality. I diamonds have inclusions obvious even to the naked eye. Furthermore, these inclusions may even affect the diamond’s durability or wearability, especially I3 stones.



Understanding Diamond Cut

diamond cut
Diamonds are renowned for their ability to transmit light and sparkle intensely. We often think of a diamond’s cut as shape (round, heart, oval, marquise, pear), but what diamond cut actually does mean how well a diamond’s facets interact with light. A diamond cut is the summary of a diamond's proportions evaluated using the attributes of brilliance, fire, and sparkle. While high marks of color or clarity affect a diamond, it's the cut that defines its proportions and ability to reflect light. Precise artistry and workmanship are required to fashion a stone so its proportions, symmetry and polish deliver the magnificent return of light only possible in a diamond.
Achieving the best cut for a diamond reflects in the stone’s final beauty and value. And of all the diamond 4Cs, it is the most complex and technically difficult to analyze. To determine the cut grade of the standard round brilliant diamond, GIA calculates the proportions of those facets that influence the diamond’s face-up appearance. When a diamond interacts with light, every angle and every facet affects the amount of light returned to the eye. This is what gives it its face-up appearance.
A diamond’s proportions determine how light performs when it enters the diamond. If light enters through the crown and goes out through the pavilion, the diamond will look dark and unattractive. Diamonds with different proportions and good polish make better use of the light, and will be bright, colorful, and scintillating. A beautiful diamond looks the way it does because of three optical effects:
  • Brightness: Internal and external white light reflected from a diamond

  • Fire: The scattering of white light into all the colors of the rainbow

  • Scintillation: The amount of sparkle a diamond produces, and the pattern of light and dark areas caused by reflections within the diamond  

The GIA Diamond Cut Scale 

The GIA Diamond Cut Scale for standard round brilliant diamonds in the D-to-Z diamond color range contains 5 grades ranging from Excellent to Poor and is the definitive scale for classifying diamond cuts. The Cut Grade of a diamond directly impacts its beauty; if a diamond is designed, cut, and finished properly, it will have a much more desirable appearance, even when compared to diamonds of higher color and clarity grades.
gia diamond cut scale


GIA’s diamond cut grade also takes into account the design and craftsmanship of the diamond, including its weight relative to its diameter, its girdle thickness (which affects its durability), the symmetry of its facet arrangement, and the quality of polish on those facets.
diamond shapes
Cut is oftentimes confused with the shape of the diamond but cut refers to a stone’s facet arrangement. Although, the term “cut” can describe a fashioned diamond’s shape. Shape refers to the outline of the stone. The most common diamond shape used in jewelry is round. Shapes other than the standard round brilliant are called fancy cuts. They’re sometimes called fancy shapes or fancies. Fancy shapes also have names of their own, based on their shapes. The best known are the marquise, princess, pear, oval, heart, cushion, and emerald cut.


Diamond Carat Weight Measures a Diamond’s Apparent Size

diamond carat weight

The term carat is often misunderstood. It refers to a diamond's weight, not its size. Another misperception is that a larger carat weight is always better than a smaller carat weight. While it’s true that a big rock can be a status symbol, carat weight is not related to sparkle. Beautiful sparkle is the result of a well-crafted cut. In fact, a high carat weight diamond with a poor cut may look smaller than a diamond with a smaller carat weight and a very good cut.

While now you know what carat means, it’s also important to remember that a diamond’s value is determined using all of the 4Cs, and not just carat weight. Many goods are sold by weight—by the kilogram, ounce, pound, or ton. Even people who have never bought a diamond are used to the idea that weight and price are related. They understand that a larger diamond is probably more valuable than a smaller one. 


Diamond weights are stated in metric carats, abbreviated “ct.” One metric carat is two-tenths (0.2) of a gram—just over seven thousandths (0.007) of an ounce. One ounce contains almost 142 carats. A small paper clip weighs about a carat.

The metric carat is divided into 100 points. A point is one hundredth of a carat.
Diamonds are weighed to a thousandth (0.001) of a carat and then rounded to the nearest hundredth, or point. Fractions of a carat can mean price differences of hundreds—even thousands—of dollars, depending on diamond quality.

Over a carat, diamond weights are usually expressed in carats and decimals. A 1.07-carat stone, for example, would be described as “one point oh seven carats,” or “one oh seven”. Weights for diamonds that weigh under a carat are usually stated in points. A diamond that weighs 0.62 carat is said to weigh “sixty-two points,” or called an “sixty-two pointer.”

The relationship between rarity, weight, and value can be surprising. People know that a pound of sugar costs twice as much as a half-pound of sugar. But diamonds aren’t a commodity like sugar. Their price depends on a number of variables—weight is just one of them. So it’s not always easy to understand, or explain, why a 1-carat diamond is worth, say, $6,000, while a 2-carat diamond of similar quality might be worth $15,000.

All else being equal, diamond price increases with carat weight, because larger diamonds are more rare and more desirable. But two diamonds of equal carat weight can have very different values (and prices) depending on three other factors within the 4Cs: Clarity, Color, and Cut. It's important to remember that a diamond's value is determined using all of the 4Cs, not just carat weight.


Understanding diamond terminology is essential if you’re going to make a smart purchase decision. “Total carat weight” (abbreviated tcw) is the combined weight of all the diamonds in a piece of jewelry that only contains diamonds.

For example, an engagement ring set with many small melee diamonds weighing 2.15 tcw will cost significantly less than a solitaire engagement ring set with a single 2.15 ct diamond. Again, think size/rarity/price.

If an engagement ring has gems other than diamonds in it, the combined weight of all the stones is called “total gem weight.”  



The importance of understanding the evaluations of diamond quality lies in your ability to use them to find the diamond that is your best match. When starting your search for diamonds in Boca Raton, keep the 4C's of diamonds in mind and you will be well on your way to finding the diamond of your dreams! Stop by Devon's Diamonds & Decor to view our beautiful selection of diamond jewelry.
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