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. Here's the 'secret' to how a diamond sparkles:
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.
These measurements and percentages are different for each diamond, and are all taken into account in the evaluation of a diamond's cut. In fact, each diamond shape (heart, round, oval, emerald, etc.) has its own set of guidelines for what makes a Premium or Good cut.
An 'ideal cut' is a specific set of guidelines that delineate the proportions that give a diamond the highest amount of fire and brilliance.
Although the proportions of an ideal cut vary depending on the source you talk to (from jeweler to jeweler, country to country), there are certain ranges that are generally accepted as capable of evoking the most desirable fire and brilliance from a stone. These ranges must cause the light entering the diamond to be reflected and dispersed through the table (top), not through the sides or bottom.
But most of all, an ideal cut diamond must be cut to bring out the stone's brilliance and fire, not retain the most weight from the rough cut stone.
Color: 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 diamond color grading system 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
Diamonds found in nature come in colors ranging from colorless to slightly yellow
or brown, to more rare and costly pink, green or blue stones (commonly referred
to as 'fancy' diamonds). Excluding 'fancy' diamonds, the ideal color for a diamond
is colorless, although this is extremely rare.
A diamond's color is most accurately determined when it is not mounted in a setting, since settings can introduce tints of their own color into the diamond. This is more evident in yellow gold settings, and less so in white gold and platinum settings. Even a trained professional can't always tell the difference between close grades of color in a diamond if it is still mounted in a setting. For this reason, gemological laboratories such as the Gemological Institute of America (GIA) and American Gemological Society (AGS) will only grade diamonds that are unmounted.
Diamonds with a color grade of D, E or F are considered colorless; G, H, I and J are near colorless; K, L and M have a faint yellow tint; N, O, P, Q and R have a very light yellow tint and S, T, U, V, W, X, Y and Z are light yellow. A diamond that is a D color is absolutely colorless, and is therefore the most valuable. However, it's important to understand that color alone does not determine the value of a diamond. All '4Cs' must be taken into account. A diamond of D color that has imperfections or is poorly cut is not as valuable as a stone of a lower color grade that has a superior cut and clarity.
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):
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.
A diamond's ability to refract and reflect light is what makes it so brilliant and so valuable. The way it does this is by allowing light to enter the top of the stone, reflect off the facets that have been cut by a diamond craftsman, and reflect out the top of the stone to your eye. So, the fewer obstacles to this pathway there are, the greater the diamond's clarity will be, which increases the diamond's value (all other characteristics being equal).
Most diamonds contain some blemishes (crystals, clouds, or feathers), which can be found inside the stone (called inclusions). Surface blemishes are not considered a major concern, since they can often be polished away. Crystals are mineral deposits trapped inside the diamond; clouds are small specks or hazy areas that give a milky appearance; and feathers are small cracks that are shaped like a bird's feather.
Naturally, inclusions that don't impede the light's passage through the diamond or visibly decrease its beauty will not have a substantial effect on its value. It is more important that any blemishes do not affect the stone's attractiveness or durability, than that the diamond be 'perfect'.
A diamond's clarity is measured using a jeweler's loupe (a small magnifying glass used to view gemstones) under 10-power magnification. The FTC requires all diamond grading be done under 10-power magnification; any inclusions not detected under this magnification are considered to be non-existent.
Carat is not a measure of a diamond's size, since cutting a diamond to different
proportions can affect its weight. (The word 'Karat' 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:
Note: the diamonds illustrated are not shown actual size.
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 Cs-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.
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 1-carat diamond has 100 points, a 3/4 carat has 75 points, etc. 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.
