Earth and Sea Gem Company

THE FAMOUS 4 C'S

Only high-quality diamonds are suitable for use as gems. In judging the quality (and therefore the value) of a cut diamond, a buyer must take into account four criteria, known as the “four C’s”: color, clarity, cut and carat weight.

Color

The color of diamonds varies from colorless (most rare and precious) to many shades of yellow (less rare). Slight tints of yellow make a diamond less rare, but some people prefer the personality it gives a stone of good make and clarity. The color grading starts at D for perfectly colorless stones, and gives a Z color grade to diamonds having a noticeable yellow tint, with every letter between indicating the many gradations possible. Below is an outline of the color grading:

D, E, F -colorless
G,H,I, J – near colorless
K, L, M – faint yellow
N thru R – very light yellow
S thru Z – light yellow

Some helpful buying guidelines:

If you want perfection regardless of cost -- go for D color

If you want excellent quality and beauty -- go for E or F colors (still colorless to any eye)

If you want a larger stone for your money without sacrificing appearance -- go for G, H, or I colors (near colorless)

If you like very faint yellow tints -- go for colors like J, K, L, or M (you can see the slight tint when next to a more colorless diamond or when set in a white metal like platinum)

Clarity

The presence or absence of internal blemishes and flaws determines clarity. These are generally referred to as inclusions. Where the inclusions lie, their size, and their type determine the value of the stone. Inclusions are rated as follows:

FL = Flawless
IF = Internally Flawless — minor surface blemishes
VVS1-VVS2 = Very, Very Small inclusions
VS1-VS2 = Very Small Inclusions
SI1-SI2 = Small Inclusions
I1-I2-I3 = Imperfect — inclusions visible to the eye

Slight inclusions, although they reduce the value of a diamond, do not take anything away from its beauty. Most diamonds have some internal or external "flaws," but you should decide based on how much they are visible and how much that means to you. Usually, flawless to the naked eye (SI-1 or better) is quite sufficient for anyone concerned about beauty but not wanting to pay extra for rarity you can't see.

Cut

The final criteria buyers use in determining the quality of a diamond is its cut. The cut is the proportion and shape of the stone, as determined during the diamond-cutting procedure.

The Proportion:

Proportion is the single most important factor, because it determines the flow of light more than other quality factors. Proportions that are too deep or too shallow both allow light to leak out the bottom and lessen the amount of light that strikes your eye.

Proportions determine a diamond's brilliance (amount of light reflected back to your eye), fire (the flashes of color due to prismatic separation into the colors of the rainbow) and scintillation (sparkling movement of light as you move the diamond).

Below are the approximate proportions to create a round diamond of maximum beauty, achieving an excellent balance between brilliance, fire and scintillation. (NOTE: These proportions only apply to round diamonds. Detailed guidelines have not yet been determined for other shapes.)

In addition to the proportions, polish effects the final cut grade too. A well-polished diamond produces sharp sparkle and undistorted brilliance and fire. If the polish is poor, even a well-proportioned, symmetrical diamond can look dull or fuzzy.

Ideal Cut diamonds from many manufacturers have become popular in the past few years, and for good reasons. Stones with these ideal proportions are noticeably more beautiful to most people. These are in high demand, however, and usually require more loss of the rough to achieve ideal proportions. These factors combine to cause a slight premium in price.

The Shape:

Diamonds may be cut in different shapes with the most common shapes being round (brilliant cut) and what are referred to as fancy cut diamonds including princess, emerald, cushion, radiant, oval, pear, heart and marquise. Below are some pictures of each shape:

Carat

The weight/size of a diamond is measured in carats. One carat is divided into one hundred segments called "points." As in the decimal system, one hundred and twenty five points equals one and a quarter carats.

Carat weight has a great deal of influence on the price of a diamond. Since larger stones are more rare in nature, they are more expensive as well. For instance, one diamond weighing 2 carats will always cost much more than two diamonds of the same quality weighing 1 carat each.

It’s difficult to imagine the size of a diamond. Below is a chart that can help give you an idea of a round diamond weight size in millimeters.

What shapes do diamonds come in?
There are eight diamond shapes that are most commonly offered by fine jewelers:

Round diamonds
Princess diamonds
Marquise diamonds
Oval diamonds
Pear-shaped diamonds
Emerald diamonds
Radiant diamonds
Heart diamonds
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