DIAMONDS-Grades, shapes, cuts, color, clarity, carat!!! What do all these terms mean?

Diamonds are an integral part of a romantic relationship –be it heterosexual or lesbian or gay or any other. We talk about engagement and wedding rings and most of them have diamonds in them. Now non-diamond rings are increasingly used for this occasion but as they say: 

  “Diamonds are forever.”

Diamonds are colorless precious stones that have for generations been used for rings and other jewelry pieces. But have you ever wondered how these invaluable stones are graded? What are the various cuts that they talk about? And how do you value them? 

Different and popular diamond cuts {Source: Empress Diamonds]

The grading system of diamonds 

The American Gem Society has a classification that grades these precious stones. These grades are from 0 that is the highest grade to 10 which is the lowest grade. Thus a grade 3 is higher than a grade 5 diamond. It has less color and also is rarer to find. Hence it is more costly. This grading is based on diamond cut, diamond color, clarity and then carat weight. The diamond cut has the greatest part to play in this grading. While writing its description, a diamond with finest cut that is colorless, free of inclusions and blemishes, and weighs 1 carat would be put in this form: 0/0/0-1.000 carat. 

 For the cut scale, the numbering and grades are as follows: 0 is AGS ideal cut, 1 is excellent, 2 is very good, 3 and 4 are good, 5, 6, and 7 are fair, and 8, 9, 10 are poor. 

 As regards the color, these are graded into colorless-grades 0, 0.5, 1, near colorless-grades 1.5, 2, 2.5, 3.0, faint-grades 3.5, 4, 4.5, very light -5.0 to 7.0, Light-7.5 to 10.0 to fancy yellow. 

 Based on clarity, it would be flawless as 0, very, very slightly included as 1 and 2, very slightly included as 3 and 4, slightly included as 5, 6, 6.5, and included 7 to 10. 

 Diamonds and carat

The word carat comes from the word Carob seed that was used as a measure by the ancient diamond traders. It is different from Karat that is used to refer to gold’s purity. A carat is equal to 0.2 grams. This is the size of a paper clip. But two diamonds of same carat may have different costs due to their color, clarity, and cut. One carat cost is usually around $ 1800-12000. Hence, as the size increase, the cost increases. Larger diamonds are rare to find. And the cost increases not only in total but also cost per carat. The price per carat might approximately double with each carat thus increasing the total cost. Also, a one carat round cut diamond has a diameter of 6.50 mm and a crown surface of 33.2 sq. mm. A 2 carat diamond’s diameter is 8.20 mm and crown surface area is 52.8 sq. mm. A 3 carat diamond’s diameter is 9.40 mm and crown surface area is 69.4 sq. mm. Thus the size of the diamond increases more than the diameter as the carat is increased.

The diamond cuts [Source: Frank Jewelers]

Also, similar cut shape and carat weight diamonds may still appear different in size due to the deep cut on one of them. Hence in that particular diamond, more part of the diamond is hidden below and the diamond therefore appears smaller in size. Besides, diamonds size also appears big or small based on the cut shape. A marquise-cut (see below) 1 carat diamond appears larger in size compared to a round cut 1 carat diamond. Thus longer shapes (oval, marquise, pear, emerald) appear larger in size compared to round or square shapes. Marquise appears by far the largest in size even with similar carat value. It appears larger than another marquise diamond of lesser carat value but a deeper cut. 

 Diamond shapes or cuts

The diamonds are cut in various shapes. The round shape is by far the most popular and most costly. The rarest cut is Asscher. Marquise is the largest appearing one for similar carat. The popular 10 shape cuts are round, princess, oval, marquise, pear, cushion, emerald, asscher, radiant, and heart-shape cuts. The following are the sizes and crown surface area of different cuts of the diamond but with similar carat. 

Size	Round	Princess	Oval	Marquise	Pear	Cushion	Emerald	Asscher	Radiant	Heart
Lengthxwidth	6.50x6.50	5.58x5.46	7.76x5.69	10.18x5.33	8.67x5.66	6.12x5.69	6.57x5.09	5.68x5.60	6.35x5.39	6.14x6.89
Crown (sq.mm)	33.2	30.2	33.3	36.9	34.0	29.2	31.8	28.7	32.1	28.1

This below picture shows the sizes of the different cuts of different carats

Different diamond cuts and carats and their sizes [Source: Lumera Diamonds]

Thus, the value of a diamond is based on 4 Cs namely its carat, color, clarity, and cut.