There are two recognized diamond grading systems that are used globally. The first grading system was developed by the Gemological Institute of America or GIA, and it is the most widely used grading system. The other was developed by the American Gem Society or AGS, which is primarily used by a group of AGS affiliated retail stores. For our purposes, we will utilize the GIA grading system to explain the 4Cs of diamond quality, which are color, clarity, cut and carat weight. If you would like to see the conversion chart visit Cool School.
We often think of a diamond’s cut as shape (for example, a round or princess cut), but in reality, a diamond’s cut grade has to do with how it interacts with light. It’s the most difficult to analyze and the most important diamond feature.
In the diamond trade, the cut of a diamond is referred to in terms of its “proportions,” which include table diameter, crown angle, pavilion depth, angle total depth percentage and length to width ratio. In the past, proportions were simply classified as Good, Very Good, or Excellent, but now, for a standard round diamond, there are 5 grades from Excellent to Poor. The diamond cut grade takes into consideration the weight of the diamond relative to its diameter, the girdle thickness and the symmetry and polish of each facet. Ultimately, each influences the diamond’s face up appearance and affects how the diamond converts white light into a rainbow of colors called “brightness,” “dispersion,” and “scintillation.”
What you will learn in Cool School is the cut has a major impact on not only the beauty of a diamond, but also the value, as much as 40%. Take a quick look at the three types of round brilliant cut diamonds Bellman’s has to offer and see why we offer the most desirable round brilliant cut diamonds in New England.
At Bellman’s, all of our diamonds are Ideal Cut. In 1919, Marcel Tolkowsky developed a set of “ideal” proportions for a diamond that allow for optimum brilliance. Since then, new advancements in cutting have been discovered and add to his groundwork. Two of the cuts that have emerged are the Hearts and Arrows Cut and the Forever After Cut.
Only 1% of all the diamonds sold in the world are Ideal Cut.
The Hearts and Arrows Cut diamond is a combination of the Ideal Cut, with the precise proportions explained above, but also includes a manipulation of the individual facets, thus reducing light leakage and increasing the brilliance by up to 300%! This cut also produces either a distinct pattern of eight hearts or eight arrows, depending on which side of the diamond you are looking through. Check out the pattern in the diagram.
You might have heard of similar branded diamonds and our Hearts and Arrows Cut diamonds are the same! The only difference is that we cut our own Heart and Arrows diamonds and because we don’t spend millions on marketing, we can offer the Hearts and Arrows cut for nearly the same cost of the Ideal Cut diamonds, saving you over 40%.
Diamond color refers to the actual body color of a diamond and can range from colorless (absence of color) to light yellow. A diamond that has no hue has more value than one with more color.
The scale begins with the letter D, representing colorless, and continues, with increasing presence of color, to the letter Z.
Diamonds are formed in nature and during the process, a variety of internal characteristics called ‘inclusions’ and external characteristics called ‘blemishes’ can occur.
When determining a diamond’s clarity, the number, size, nature, and position of inclusions and blemishes, as well as how they affect the overall appearance of the diamond is considered. While no diamond is perfect, the higher the clarity grade, the higher the overall quality.
Diamond clarity is graded using a 10x power microscope, not by the naked eye. 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 Internally Flawless (IF) No inclusions visible under 10x magnification Very, Very Slightly Included (VVS1 and VVS2) Inclusions so slight they are difficult for a skilled grader to see under 10x magnification Very Slightly Included (VS1 and VS2) Inclusions are observed with effort under 10x magnification, but can be characterized as minor Slightly Included (SI1 and SI2) Inclusions are noticeable under 10x magnification Included (I1, I2, and I3) Inclusions are obvious under 10x magnification which may affect transparency and brilliance
Similar to many other commodities, diamonds are sold by their weight. Carats are part of the metric system and are the measurement used for diamonds. A one-carat diamond is equivalent to 1/5 of a gram. Therefore, a five carat diamond would weigh exactly one gram. A carat can also be subdivided into 100 points, so a .75 carat diamond may be referred to as a “seventy-five pointer.” A diamond that weighs greater than one carat is expressed in carats and two decimal places, i.e., 1.75 carats. A diamond’s value is determined by a combination of all of the 4C’s, not just carat weight. If the cut, color and clarity were equal, a larger diamond would be more expensive due to the rarity and the desirability.
Nothing is more powerful than knowledge. If you want to succeed in purchasing the best diamond for the best price then it’s time to go to school, Cool School. It has been proven that consumers who finish Cool School know more about diamond grading than most people selling diamonds. Educate yourself today and reap the benefits of my 35 years of diamond grading experience.
— Enjoy, David Bellman, G.G. GIA