Learn The 4Cs

 

Put simply, there are four universally accepted characteristics that all diamonds are graded by. They are known as the 4Cs : 

Cut, Color, Clarity and Carat weight

It is the combination of these four C that determines a diamond's value. By changing any of the characteristics, you can dramatically affect the diamond's value, all other factors being equal.

Understanding Carat Weight

A diamond's weight is measured in what is known as a Carat? which is a small unit of measurement equal to 200 milligrams. Carat is not a measure of a diamond's size, since cutting a diamond to different proportions can affect its weight. (The word Carat is used to express the purity of gold, and is not used in relation to diamonds.)  Here is a diagram that shows the relative size of various carat weights in a diamond that is cut to the same proportions:

The most important thing to remember when it comes to a diamond's carat weight is that it is not the only factor that determines a diamond's value. In other words, bigger does not necessarily mean better. All four C's Cut, Color, Clarity and Carat Weight must be balanced in order to arrive at a diamond that fits your budget. None of the 4Cs is mutually exclusive, nor is any one more important than the others.

More on Carat:

The word carat actually comes from the word carob (as in carob seeds), which is how ancient cultures measured the weight of diamonds on their scales. In 1913, however, the weight was standardized internationally and adapted to the metric system.

Although they can be measured when mounted in jewelry, diamonds are most accurately weighed when they are not mounted in a setting. In fact, gemological laboratories such as the Gemological Institute of America (GIA) and American Gemological Society (AGS) will only grade diamonds that are unmounted. A diamond grading report will tell you the exact carat weight, to the nearest hundredth of a carat, for that particular diamond. 

Each Carat is divided into 100 parts called 'points.' So a one carat diamond has 100 points. Points in a fraction of one carat are measured within ranges, so that a 3/4 carat diamond may have between .69 and .82 points and still be considered a 3/4 carat. Here's a table of size and weight ranges:

Carat Fractions and Their Decimal Equivalents:

Fraction Decimal Equivalent

1/10 = .09 ─ .11
1/8 = .12 ─ .13
1/7 = .14 ─ .15
1/6 = .16 ─ .17
1/5 = .18 ─ .22
1/4 = .23 ─ .28
1/3 = .29 ─ .36
3/8 = .37 ─ .44
1/2 = .45 ─ .58
5/8 = .59 ─ .68
3/4 = .69 ─ .82
7/8 = .83 ─ .94
1.0 = .95 ─ 1.05

Remember, all diamonds are not created equal. Two diamonds of equal Carat Weight may vary substantially in price due to their Cut, Color and Clarity. Also, a diamond's weight can be 'hidden' in different parts of the stone. 

For example, you can have a well-cut diamond, whose weight is distributed properly, a diamond that is cut too shallow to make it wider and heavier, but not the most brilliant, or one that is cut too deeply, to add weight to the bottom of the stone - again compromising its ability to radiate maximum brilliance. Visit Cut for more information.

The bottom line

The carat weight of a diamond is an extremely important determining factor in its value. Diamonds are valued on a per-carat basis. For example, a diamond of exceptionally high quality may sell for $20,000 per carat, while one of lesser quality may sell for $1,000 per carat. So, a three-carat stone could be $60,000 or $3,000, depending on its per-carat price. 

Diamond values also increase disproportionately as the size of the stone increases. In other words, a two-carat stone will not necessarily cost twice per carat than a one-carat stone. It could cost much more, since diamonds are rarer in larger sizes. 

As you take a stone of a particular cut, clarity and color and move its carat weight to the next price category, you may see quite a large increase in the price per carat. Remember that size isn't everything. When choosing a diamond, all 4Cs must be taken into account. The key is to strike a balance among them, while still working within your budget.

Understanding Color

The most important thing to know about color when it comes to diamonds is, in general, the less color a diamond has, the more valuable it is, all other factors being equal. Diamonds are found in nature in a wide range of colors, from completely colorless (the most desirable trait) to slightly yellow, to brown. So-called fancy color diamonds come in more intense colors, like yellow and blue, but these are not graded on the same scale.

The color grading system for diamonds uses the letters of the alphabet from D through Z, with D being the most colorless and therefore the rarest and most valuable, and Z having the most color within the normal range, and being the least valuable, all other factors being equal. A diamond's color is determined by looking at it under controlled lighting and comparing them to the Gemological Institute of America's color scale, which is based on a set of diamonds of known color. Here is a diagram showing how a diamond's color is graded:

Understanding Clarity

Another vital grading characteristic in diamonds is their clarity. This refers to the number, position and size of the inclusions that occur naturally inside diamonds. The fewer and less obvious the inclusions, the more valuable the diamond. Here is an illustration that shows the clarity grading scale that has been established by the world's foremost authority on diamonds, the Gemological Institute of America (GIA).   (Note: Diamonds are shown under 10X magnification):

F Flawless
The diamond shows no inclusions or blemishes of any sort under 10X magnification when observed by an experienced grader. 
Note: Truly flawless or internally flawless (F or IF on the GIA's grading scale) diamonds are extremely rare.
IF Internally Flawless. 
The diamond has no inclusions when examined by an experienced grader using 10X magnification, but will have some minor blemishes.
VVS1, VVS2  Very, Very slightly included. 
The diamond contains minute inclusions that are difficult even for experienced graders to see under 10X magnification.
VS1, VS2 Very slightly included. 
The diamond contains minute inclusions such as small crystals, clouds or feathers when observed with effort under 10X magnification.
SI1, 
SI2 
Slightly included. 
The diamond contains inclusions (clouds, included crystals, knots, cavities, and feathers) that are noticeable to an experienced grader under 10X magnification.
I1, 
I2, 
I3
Included. 
The diamond contains inclusions (possibly large feathers or large included crystals) that are obvious under 10X magnification and may affect transparency and brilliance.

It is these inclusions or blemishes that give each diamond its own unique fingerprint, making your particular diamond truly yours. In fact, the independent grading report that comes with every diamond we sell will show a diagram indicting any characteristic your diamond, indicating any blemishes your diamond may have, as well as their location. 

The most important thing to remember when it comes to clarity is that a diamond's inclusions should not be noticeable to the naked eye, nor should they be so excessive that they affect the diamond's durability.

Understanding Cut

The only one of the 4Cs that is within our control is a diamond's cut. Cut is the result of a craftsman's skill in transforming a rough diamond into a breathtaking gem. A diamond has facets that allow light to enter it, become refracted, and exit in a rainbow of colors. So it follows that a better cut diamond does a better job of dazzling us with its beauty. 

As you can see, the diamond with the correct proportions does a more effective job of refracting light out the top of the stone to your eye. The less-than-ideal cut diamonds allow some light to become lost out the bottom.