Understanding Diamond Grading

The cost of a diamond has a lot to do with its grading, size and rarity. On the case of some more notable diamonds, the history surrounding it can outweigh the other factors and drive up its value regardless of the grade. The things that determine the grade of a diamond or any other precious stone are commonly referred to as the four “C’s” stand for color, clarity, carat and cut.  There are scales used as a standard across the industry that help dealers price their stones, diamonds that are graded more to the left side of the scales have a higher cost than those that fall closer to the right of the scales. Many consumers focus on the clarity of a diamond the most and while it’s important, the cut and color are the factors that affect the overall look of the stone the most. Let’s take a closer look at the four “C’s” to gain a better understanding of the grading process.


Diamond Clarity
Clarity of a diamond or other precious stone is determined through a number of factors. Position, nature, size, number, and color are the main, while inclusions and blemishes also factor in. Natural diamonds are formed through intense pressure of volcanic rock; irregularities are usually formed when the diamond is still interred in the liquid magna. Being mostly pure carbon, any minerals that happen to be nearby during the crystallization process effects the final clarity of the diamond. A diamond or precious stone is placed in good lighting and then magnified 10X to undergo the labeling process by an expert grader. The most clear or pure stone can secure a rating of flawless, while the most heavily included stones can get the lowest rating of I-3. The final grade is determined by the amount of inclusions a diamond has, as well as how easy blemishes are seen.

 Carats (Diamond Weight)

Diamond Weight
All precious gemstones are weighed by the carat scale. The weight measurement was developed in ancient times by using the seed from the pod of a carob tree often found in tropical climates. Until recent times, the system was used to weigh all precious stones. A single carat has a subdivision of one hundred points. For example, if a diamond is allotted 75 points, then it has a weight of 3/4thcarats, or .75 ct. Each gram is made up of five carats which allows for proper measurement of larger diamonds or precious stones.

 Diamond Colour

Diamond Colour

In an ideal setting, a white diamond should be as clear as drought of spring water, meaning it should be colourless. Of course, nature being what it is often adds certain amounts of colour under varying circumstances. These degrees of colour have a scale by which they are measured ranging from “D” which is no colour all the way to “Z” which signifies a diamond being deeply coloured.

There are also other ranges that are special such as vivid, fancy and rich. These types of diamonds are not clear in any sense making their uniform coloring unique. One such famous diamond is the Canary diamond which has a natural yellow colour. In many labs, a colourimeter is used to pinpoint color grading, but there is no substitute for a well trained grader comparing a diamond’s colour to that of one of the Master Stones.

 Diamond Cut
The cut of a diamond is what determines its brilliance, aesthetic value and over sparkle. The cut also is important since a poorly cut stone can be prone to breakage. On the contrary, diamonds are rarely cut for simply weight alone; its final appearance is always taken into consideration. There is a standard proportion scale used by all diamond cutters that is used to show the percentages and angles of both brilliant cut and round cut diamonds. This is available to the public but mostly used by graders and cutters. If you look at a diamond and it doesn’t catch your gaze though at least a small glimmer or shine, it signifies the poor cut of the stone which also leads to a decrease in its value.

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