Diamond

This brilliant gemstone radiates light to its viewer and represents love, beauty and commitment. A diamond’s cut, color, clarity and carat weight are the four attributes that determine its cost and overall value. Known as the four C’s these qualities are used by gemologists to grade a diamond and are important considerations when purchasing.

Diamond is the hardest known substance in the world. The largest diamond ever discovered was found in South Africa and weighed 1.33 lbs (3,106 carats).

The Anatomy of a Diamond

American Gemological Society (AGS®)
Ideal Cut

A measurement of the diamond’s weight, carat (abbreviated ct.), is a unit of mass equivalent to 200 milligrams. This measure of weight is used for diamonds, gemstones and pearls.
A diamond’s weight is commonly referred to as points. A carat is divisible by 100 points, each point is equivalent to 2 milligrams. One hundred, one pointers (.01) are equivalent to one carat. On a price per carat basis, a one carat gemstone is significantly more expensive than multiple smaller gems that weigh the same amount. The larger the gemstone, the higher the price per carat. It is far less common to find large diamond rough from which a diamond is cut, therefore as a diamond’s carat weight increases, so does its price per carat.

While a gemstone’s weight in carats correlates to its size, the cut of a gemstone has a significant impact on its perceived size. Two diamonds that are the exact same carat weight may appear to be different sizes based on their cut. For example, if a diamond is cut shallow its diameter when viewed from the top will be larger than a diamond with a larger depth. When comparing the size of two diamonds, look at their length, width and depth measurements in millimeters.
A finished jewelry item will often have the abbreviation, CTW (carat total weight) indicating the weight of all of the diamonds added together.

Do not confuse a diamond’s cut with a diamonds shape. Cut refers to the proportions of a diamond, its symmetry and polish. This important attribute is the leading factor in the diamonds light performance or brilliance. When properly cut to proportion, light that enters a diamond is returned out the top of the diamond. A diamond that is too shallow or too deep allows light to escape out the sides or bottom of the diamond resulting in a dull diamond with less sparkle.

Researchers using objective methods of measuring light performance have conducted studies to find the optimum proportions to enhance a diamond’s performance of light, thus increasing its brilliance, dispersion and scintillation. A set of guidelines has been created based on this research. Each unique piece of diamond rough is considered as master gem cutters apply the guidelines to reveal the largest most brilliant diamond possible.
The cut attribute ranges from Poor to Excellent.

A white diamond’s color, or more specifically its lack of color impacts its value. The less color, the higher the color grade. When grading a diamond, gemologists view the diamond in a controlled environment where lighting and conditions are consistent. Gemologists use a set of masterstones for comparison. The diamond is viewed next to the masterstones within this environment to classify the diamonds color.
The Color attribute ranges from D (colorless) to Z (light yellowish).

Fancy-color diamonds are yellow or brown diamonds that have more color than the Z masterstone, or diamonds that exhibit colors other than brown or yellow. Fancy-colored gemstones are graded on a different color scale.

A diamond’s clarity is the measure of imperfections called blemishes and inclusions. The location, size, amount and type of flaws determine its clarity. Surface blemishes and internal inclusions can alter the brilliance of a diamond.
The clarity scale ranges from flawless (no inclusions or blemishes visible under 10X magnification) to included (inclusions or blemishes visible to the naked eye). The scale (illustrated below) begins (FL, IF) followed by very, very slight (VVS1,VVS2), very slight (VS1,VS2), slightly included (SI1,SI2), and included (I1,I2,I3).