How is the Value of a Diamond Determined? Understanding the Grading of the 4Cs of Diamonds
Grading Diamond Color
Since light source and background can have a significant impact on a diamond’s appearance, diamond color is graded in a standardized viewing environment against color masters. A minimum of two color graders enter their independent evaluations into the system and depending on the agreement of these grades, and the weight and quality of the diamond, it may be sent to additional graders who enter their own color opinions. The grade is not determined until there is sufficient consensus. Key Points;
- Color refers to a diamond’s lack of color, grading the whiteness of a diamond.
- A color grade of D is the highest possible, while Z is the lowest.
- Consider buying diamonds with a color grade of J or higher.
Color manifests itself in a diamond as a pale yellow. This is why a diamond’s color grade is based on its lack of color. The less color a diamond has, the higher its color grade. After cut, color is generally considered the second most important characteristic when selecting a diamond. This is because the human eye tends to detect a diamond’s sparkle (light performance) first, and color second. The finest diamonds are color graded D-J. Diamonds graded J or better are colorless or near-colorless, with color that is typically undetectable to the unaided eye.
Near-colorless. An exceptional value with slightly detectable warmth or tone.
Near-colorless. Color difficult to detect unless compared side-by-side against diamonds of better grades. An excellent value.
Colorless. Minute traces of color can be detected by an expert gemologist. A rare diamond.
Absolutely colorless. The highest color grade. Extremely rare.
What Color is Right for Me?
For the purist, look for a colorless diamond with a grade of D-F for a diamond with no discernible color.
For an excellent value in a diamond with little or no noticeable color to the unaided eye, look for a near-colorless grade of G-I
Now that you understand how color affects the white look of a diamond, you are ready to learn about clarity. For more on diamond Color and an interactive scale, go to http://www.4cs.gia.edu/EN-US/diamond-color.htm
Grading Diamond Clarity
Diamond clarity is graded under standard viewing conditions with 10x magnification. The preliminary grader carefully examines the diamond in order to identify clarity/finish characteristics and evidence of any clarity treatments such as fracture filling or laser drilling.
A minimum of two graders assigns their impression of the diamond’s clarity, polish, and symmetry. Next they plot the clarity characteristics on the diagram most representative of the diamond’s shape and faceting style. Key Points;
- Clarity is a measure of the number and size of the tiny imperfections that occur in almost all diamonds.
- Many of these imperfections are microscopic, and do not affect a diamond’s beauty in any discernible way.
Much is made of a diamond’s clarity, but of the Four Cs, it is the easiest to understand, and, according to many experts, generally has the least impact on a diamond’s appearance. Clarity simply refers to the tiny, natural imperfections that occur in all but the finest diamonds. Gemologists refer to these imperfections by a variety of technical names, including blemishes and inclusions, among others. Diamonds with the least and smallest imperfections receive the highest clarity grades. Because these imperfections tend to be microscopic, they do not generally affect a diamond’s beauty in any discernible way.
Flawless, Internally Flawless: No internal or external imperfections. Internally Flawless: No internal imperfections. Very rare.’
Very, Very Slightly Included: Very difficult to see imperfections under 10x magnification. An excellent quality diamond.’
Very Slightly Included: Imperfections are not typically visible to the unaided eye. Less expensive than the VVS1 or VVS2 grades.’
Slightly Included: Imperfections are visible under 10x magnification, and may be visible with the unaided eye. A good diamond value.’
Included: This grade of diamonds will have minor inclusions that may be visible to the unaided eye.’
Poor grade clarity
What Clarity Grade Is Right For Me?
- Select an “eye-clean” diamond – one that has no imperfections visible to the unaided-eye through the crown. An excellent value, diamonds of this clarity are much less expensive than flawless (FL) or internally flawless (IF) diamonds, which are extremely rare and command higher prices.
- Frequently, imperfections in diamonds graded slightly included (SI) are not visible to the unaided eye, making them an excellent value. If you’re considering a diamond with an SI clarity grade, call to speak to a diamond and jewelry consultant who will review the diamond to ensure the imperfections are not visible to the unaided eye.
For more on Clarity and an interactive scale, go to http://www.4cs.gia.edu/EN-US/diamond-clarity.htm
Grading Diamond Cut
GIA provides a diamond cut quality grade for standard round brilliant diamonds that fall into the D-to-Z color range. To develop their Cut Grading System, GIA performed extensive computer modeling of round brilliant diamonds over a 15-year period and conducted more than 70,000 observations on actual stones to validate the research. This system can now predict the cut grade for more than 38.5 million proportion sets.
GIA’s Excellent to Poor Cut Diamond Grading System assesses the diamond’s overall face-up appearance to predict the intensity levels of brightness, fire, and scintillation (the diamond’s sparkle and interplay with light). GIA also screens every diamond submitted to determine if it is synthetic. Key Points;
- Cut is a diamond’s most important characteristic.
- It has the greatest overall influence on a diamond’s beauty.
- It determines what we generally think of as sparkle.
AB&L recommends selecting the highest cut grade within your budget. The reason is simple: of the Four Cs, no other characteristic has a greater influence on a diamond’s appearance.
A diamond’s cut grade is an objective measure of a diamond’s light performance, or, what we generally think of as sparkle. When a diamond is cut with the proper proportions, light is returned out of the top of the diamond (which gemologists refer to as the table). If it is cut too shallow, light leaks out of the bottom; too deep and it escapes out of the side.
- Excellent cut: Represents roughly the top 4% of diamond quality based on cut. Reflects nearly all light that enters the diamond. An exquisite and rare cut. The highest grades of polish and symmetry allow it to reflect more light .
- Very good cut: Represents roughly the top 15% of diamond quality based on cut. Reflects nearly as much light as the ideal cut, but for a lower price.
- Good cut: Represents roughly the top 25% of diamond quality based on cut. Reflects most light that enters. Much less expensive than a very good cut.
- Fair cut: Represents roughly the top 35% of diamond quality based on cut. Still a quality diamond, but a fair cut will not be as brilliant as a good cut.
- Poor cut: Diamonds that are generally so deep and narrow or shallow and wide that they lose most of the light out the sides and bottom. Diamonds with cut grades of poor are not recommended.
What Cut Grade Is Right For Me?
Diamonds with a cut grade of good or very good represent an excellent combination of beauty and value.
For more info on Cut and an interactive scale, go to http://www.4cs.gia.edu/EN-US/diamond-cut.htm
Diamond Carat Weight Measurement
To determine diamond carat weight, the diamond is weighed using an extremely accurate electronic micro-balance that captures the weight to the precise fifth decimal place (the nearest ten-thousandth of a carat). An optical measuring device is used to determine the diamond’s proportions, measurements, and facet angles. Key Points;
- Carat is specifically a measure of a diamond’s weight, and by itself may not accurately reflect a diamond’s size.
- We tend to evaluate diamond size by viewing it from the top because that is how diamonds are presented to us when set into a ring.
As the name suggests, carat weight specifically refers to a diamond’s weight. However, much as a person’s weight does not necessarily correlate with height, carat weight, by itself, may not accurately reflect a diamond’s size. To gain a precise understanding of diamond size, AB&L recommends considering carat weight with two other characteristics: 1) the distance across the top of the diamond measured in millimeters, and 2) the diamond’s cut grade.
It is important to measure the distance across the top of the diamond as this is how we view a stone when set into a ring. A diamond’s cut grade should also be considered because when a diamond is cut with the proper proportions, the maximum amount of light (or sparkle) is returned out of the top of the diamond. Thus, when a diamond is well cut, the light reflected out of the top makes it appear larger. In addition, much of the weight of a poorly cut diamond, for example, may be “hidden” in the base of the diamond, making the diamond appear smaller than its carat weight would imply. It is therefore possible to have a diamond of a lower carat weight, but higher cut grade, that appears larger than a diamond with a larger carat weight, but poor cut.
Once you’ve selected your cut, color, and clarity grade, it’s easy to determine the carat weight of diamond that will fit within your budget.
Much as there are 100 pennies in a dollar, a one-carat diamond is comprised of 100 points. Hence, 50 points is equal to 1/2-carat, and so on.
What Carat Weight Is Right For Me?
To choose the best carat weight of diamond, consider the size of the finger, the size of your setting, and your budget.
- If a large carat weight is important to you, yet you’re working within a strict budget, consider a diamond with a good cut, SI1-SI2 clarity, and an I or J color grade.
- Diamond prices jump at the full- and half-carat weights. Diamonds just below these weights cost significantly less, and, because carat weight is distributed across the entirety of the diamond, small size differences are almost impossible to detect.
- Keep in mind that the smaller the finger, the larger the diamond will appear. A 1.5-carat diamond solitaire looks much larger on a size 4 finger than a size 8.
- Not all settings will fit all diamond carats or shapes. If you have already selected a setting, check the diamond specifications of your ring or ask AB&L for help. If you need a special jewelry piece created, AB&L can accommodate almost any request.
For more info on Carat Weight and an interactive scale, go to http://www.4cs.gia.edu/EN-US/diamond-carat-weight.htm