The Four Characteristics That Determine Diamond quality (The 4 C's)

Two diamonds may, at first glance, look alike, but the truth is they are very different. Although they may be of equal size, each diamond has characteristics unique to itself, so they may have unique values. To understand these differences is to understand the 4 C's. Cut, color, clarity and carat-weight. It is the combination of these four characteristics that determines the value of a diamond. Let our diamond experts explain the 4 C's to you in more detail when you visit our store.

Definition In its rough state, a diamond's beauty is well concealed. Through cutting, the magnificent optical beauty of a diamond is revealed. A diamond cutter's challenge is to balance beauty with weight retention from the rough diamond crystal.

In the best-case scenario, approximately 50% of the weight is lost from the original crystal in the cutting process. Because size is important to many consumers, often cutters sacrifice diamond beauty in order to save weight, maximizing the size of the finished diamond.

Note that cut is also referred to as make.

Many people confuse cut with the shape of a diamond. The shape you select is a matter of individual taste, and today your choice is only limited by the skill and imagination of the craftsman. It is their effort during every stage of the fashioning process that reflects the maximum amount of light back to the eye. Most round, brilliant-cut or fancy-shaped diamonds possess 58 carefully angled flat surfaces, called facets, whose placement will affect the fire, brilliance and ultimate beauty of your diamond.

Optical Beauty:
The way a diamond reflects and refracts light is dazzling to the beholder. There are four factors that determine the optical beauty of a diamond: luster, brilliance, dispersion, and scintillation.

Luster The quantity and quality of light reflecting from the surfaces of a diamond.

Brilliance The amount of white light returned to the eye from the diamond.
Dispersion The amount of rainbow colors returned to the eye from within the diamond.

Scintillation The sparkle, which is the combination luster, brilliance, and dispersion when there is movement by the wearer or light source.

How Cut is Graded
In the past diamonds were analyzed, not graded, for cut by visual estimation. Today, there are several electronic machines used to determine the angles and proportions relating to the quality of cut. A diamond's finish, including polish and symmetry, is graded by human examination through a binocular microscope.

Round Diamonds - The standards for quality of cutting a round brilliant diamond have been established by AGS using nearly 100 years of research. AGS Laboratories assign a numeric cut grade; 0 to 10, 0 being best, complete with all the proportions and finish parameters for round diamonds. The AGS numeric cut grade

Fancy Diamonds - Since the proportions for fancy-shaped diamonds vary the optimal balance of luster, brilliance, dispersion and scintillation, is different for each shape. Therefore, no cut grade is assigned for fancy-shapes at this time. Research is currently underway by the AGS for the future potential in offering a cut grade for fancy-shaped diamonds.

Cut A diamond cut to optimal proportions, with optimal polish and         symmetry, with the most weight loss to produce maximum luster,         brilliance, dispersion, and scintillation. Diamonds cut to this standard are         the most valuable, with only 5% of the round brilliant diamonds on the         market cut to this standard.

        Well-Cut Diamonds that have very good optical beauty that fall just         outside of the parameters of Ideal Cut diamond. These diamonds are         priced less than Ideal cuts because they are not as rare.

        Deep Cut
This diamond will appear smaller than it weighs because it's         weight is retained in the depth. It is cut with a deep pavilion (bottom of the         diamond) that does not reflect light back through the crown (top of the         diamond). Light leaks out the pavilion producing a dark appearingdiamond         that lacks beauty. These diamonds are sometimes called nailheads due to         their dark, face-up appearance.

        Shallow Cut  Diamonds that are cut with shallow pavilions that do not         reflect light back through their crown. The light leaks out from the pavilion,         producing a washed-out or watery appearance that is not beautiful.         Weight is retained in the diameter, making the diamonds appear larger         than they weight. These diamonds are sometimes called fisheyes, due to         unsightly reflections in the crown area.

        Bow-Tie Effect dark area in the center of some fancy-shaped diamonds.         A large bow-tie in the center of a fancy shaped diamond detracts from         beauty and lowers the value.

Cut in Relation to Value
Cut is the most important factor to a diamond's beauty. Regardless of the color, clarity, and carat weight, a well-cut diamond will be beautiful. Cut is  so important to the value of a diamond that it can affect the value by 25% to over 50%.

Fancy-shaped diamonds, since they retain weight from unusual shaped rough crystals, are often less expensive then comparable round diamonds. Carat for carat, since fancy-shaped diamonds are elongated, they appear larger than round diamonds. If a consumer is interested in maximizing size appearance, they can buy a smaller, yet larger-appearing fancy shaped diamond of the same quality for less than a comparable round brilliant diamond.

When shopping for a diamond, ask a professional AGS jeweler about diamond cut quality. Physically examine diamonds with your own eyes, shop and compare, and make the best decision for you.

The seven most popular shapes of a diamond.

Brilliant Marquise Pear Emerald Oval Heart Princess


Definition The amount or presence of body color in a diamond (colorless to yellowish).

The most prized diamonds are colorless diamonds, because their beauty depends entirely upon their remarkable optical properties. In such diamonds, all the colors of the rainbow are reflected back to your eye. While the majority of gem diamonds appear to be colorless, others can contain increasing shades of yellow to brown, some of which are referred to as champagne diamonds. Other diamonds of exceptional color--red, blue, green, pink, and amber--are known as "Fancies."

The color grading scale varies from totally colorless to light color or tinted. The difference between one grade and its neighbor is very subtle. Experts never try to remember color; they use master diamonds of known color for comparison.

AGS 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
  Colorless Near Colorless Faint Yellow

AGS 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 10.0
  Very Light Yellow Light Yellow



Definition The presence or absence of inclusions within the diamond and blemishes on its surfaces. These slight birthmarks of nature generally do not affect the beauty of a stone, but they almost always affect its price. Truly flawless diamonds are extremely rare and very valuable.

Because of their unique optical properties, diamonds, more than any other gemstone, are capable of producing the maximum amount of brilliance. While minute crystals of diamond or other minerals are contained in almost all diamonds, a diamond that is virtually free of inclusions and surface markings will be judged as flawless. In these diamonds, nothing interferes with the passage of light or spoils the beauty. But these diamonds are extremely rare and will command a high price.

To determine a diamond's clarity grading, it must be examined under a 10x magnification by a trained, skilled eye. What minute inclusions there may be make every diamond unique. These are, in fact, nature's fingerprints and do not mar the diamond's beauty nor endanger its durability. Without high magnification, you may never see these inclusions. However, the fewer there are, the rarer your diamond will be.

AGS 0 0* 1 2 3 4
GIA Flawless Internally
    Minor Surface Blemishes Very, Very Small Inclusions   Very Small Inclusions  
* with a comment in the Comments section of an AGS Report

AGS 5 6 7 8 9 10
GIA SI1 SI2 I1 I2 I3
  Small Inclusions   Inclusions may be visible to the naked eye Eye Visible Inclusions Eye Visible or Dangerous


As with all precious stones, the weight--and therefore the size--of a diamond is expressed in carats.

One carat is divided into 100 "points" so that a diamond of 25 points is described as a quarter of a carat or 0.25 carats. Size is the most obvious factor in determining the value of a diamond, but now you know that two equal sizes can have very unequal prices depending on their quality. However, remember that diamonds of high quality can be found in all size ranges. Here are some other examples that show the approximate size of diamonds of varying carat weights.

0.25 carat 0.50 carat 1.00 carat 1.25 carats 1.50 carats 1.75 carats 2.00 carats 2.50
3.00 carats



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