The rarity of a diamonds will definitely add to its value, but there are the four main factors that diamonds graders look at when assessing a stone. These factors are commonly referred to as The 4 C’s of Diamonds and that stands for cut, color, clarity, and carat. Each one has its own grading scale, and a trained diamond grader will determine exactly where each stone grades in the specific category. When determining rare diamond value, you need to take into consideration both the rarity of the stone as well as the usual grading methods.
Be sure to realize that the cut of a diamond is not its shape. Diamonds come in all sorts of shapes, but the way that they are cut will greatly affect how they shine when light enters the stone. When light enters from the top of a diamond that is cut too shallow or deep, the light will exit through the sides of the diamond. In order to cut that shine, known as “brilliance” in the diamond community, the light needs to be reflected directly back out the top of the diamond, and that is achieved with a perfect cut. There are five categories in which a diamond’s cut could be graded that range from Excellent to Poor.
The colors that you may have seen on our Rare Diamond Colors page are not the ones that will be graded on this scale. White diamonds have a color scale that starts at D (colorless) and goes down to Z (yellow tint) with D diamonds being the most desirable and expensive. D, E, and F are all considered “colorless” and are commonly found in platinum and silver settings, while diamonds with a faint yellow tint can go unnoticed in gold and rose gold settings. An expert grader will be able to notice any yellow hue a diamond may possess despite appearing colorless to most.
No one wants a cloudy stone that has noticeable imperfections, so a diamond’s clarity is equally as important as the other graded areas. A gemologist will examine a stone under 10x magnification to look for any inclusions or blemished. Inclusions are found on the inside of a diamond and a blemish will be something on the outside of the stone. A top graded “Flawless” diamond will not have any imperfections and command the highest price with all else being equal. There are five other categories below Flawless that a diamond’s clarity could fall into.
The size of a diamond is measured in carats, which is a unit of weight. .2 grams is equal to one carat. A diamond grader would simply weigh the diamond and assess its measurements to find the carats of stone. While the larger the stone the higher the price generally holds true, a cloudy, yellow-tinted, poorly-cut large diamond would not appeal to many, resulting in a very low price.
When a diamond is examined by an experienced grader, it must rate well on all four of these areas to command a high value. A diamond’s value can also be based on other factors such as shape. If a certain shape is becoming more in demand from customers, it will obviously drive the value of those stones up. The 4 C’s of Diamonds are a good place to start if you’re wondering the value of your diamond.