Diamonds are a miracle of nature that we have fashioned into brilliant works of art. Diamonds form some 100 miles below the surface in an area called the upper mantle and it is in this chaotic environment that conditions for diamond formation exist, the pressure and heat are optimal for carbon atoms to cohere with each other to form a crystalline structure. The covalent bond formed between these carbon atoms is the strongest known to science and gives diamond its unique hardness. As carbon atoms combine to form a diamond crystal it is possible for other elements to become trapped as the diamond forms around them, we call these trapped elements inclusions and they are the basis on how clarity is determined.
The relative purity of a diamond is known as its clarity and the Gemological Institute of America has created a system of classifying the level of purity as a clarity grade.
Internally Flawless/Flawless (IF/F) This clarity grade is given to diamonds that have no inclusions that can be seen with 10x magnification. Internally flawless diamonds may have extremely minor surface blemishes.
Very, Very Slightly Included (VVS-1/VVS-2) These diamonds have extremely minute inclusions that are very difficult to see with 10x magnification and are impossible to see with the naked eye. VVS-1 diamond inclusions are limited to pinpoint crystals visible only through the pavilion (bottom) of the diamond. VVS-2 may have only pinpoint inclusions visible through the crown (top) of the diamond.
Very Slightly Included (VS-1/VS-2) These diamonds have minor inclusions that are somewhat difficult to see with 10x magnification and are still difficult to see with the unaided eye.
Slightly Included (SI-1/SI-2) These diamonds have inclusions that are somewhat easy to see with 10x magnification and it may be possible to see the inclusions with the naked eye.
Included (I-1/I-2/I-3) Diamonds with this clarity have inclusions that are obvious to the unaided eye and in the case of I-2 and I-3 stones may have inclusions that present a structural integrity issue. The relative opacity and beauty of these diamonds is impaired.
Just as foreign elements become trapped in a diamond so can trace elements such as nitrogen and boron become enclosed within the diamond crystal lattice, the result of this causes absorption of spectral light that we see as color within the diamond. Most common are diamonds with nitrogen, nitrogen tends to absorb light with longer wavelengths, this causes a diamond to look yellow or brown. Diamonds with boron absorb spectral light with shorter wavelengths, the result being a diamond with a blue color. Diamonds displaying a yellow or brown hue are classified in a D to Z color grading system.
Colorless Diamonds (D/E/F) Diamonds displaying no discernible color are given a grade of D, E or F depending on their level of transparency. Diamonds in this range are considered rare and demand a higher price.
Near Colorless Diamonds (G/H/I/J) Diamonds showing a very faint hue of color are given a grade of near colorless, the level of near colorlessness is determined by a set of master comparison relating to the known color.
Faint Color Diamonds (K/L/M) These are diamonds that display a more discernible hue than near colorless. It is at about this range that most consumers can begin to make out color in a diamond.
Light Colored Diamonds (N to Z) Diamonds in the N to Z range gradually show a deeper hue. Diamonds that are darker than the Z master stone are considered Fancy color.
Fancy Colored Diamonds - Diamonds come in all colors, for varying reasons we can see colors like blue, pink, green, red and orange in a diamond. If a diamond displays any level of these colors it is considered a Fancy Colored Diamond. Yellow or brown diamonds must be darker than the Z color master stone to be considered fancy.
Diamonds are shaped and polished to bring out more of the natural beauty inside them, we refer to this as the diamond’s cut. Diamonds come in a variety of shapes, the most common and identifiable is the round brilliant cut. A diamond is cut to precise proportions to ensure the angles within return the maximum amount of light. A well cut round diamond should take light in from the crown facets, reflect on the pavilion facets and return upward to the eye. The visual display will include “fire”, or the flashes of colored light, and “scintillation”, the alternating light and dark flashes seen as the diamond is moved.
Other diamond shapes include the square modified brilliant or “princess” cut. Princess cut diamonds share a lot of characteristics of round cut diamonds but their shape is that of a square or rectangle. Some people feel that the princess cut has more sparkle than its round cut cousin. Related to the princess cut is the square or rectangular cut corner modified brilliant or “radiant” cut diamond. Radiant cuts have a lot of similarities to princess cuts but the corners of these diamonds are cut 45 degrees at each corner. Related still to the round brilliant cut is the oval brilliant and marquise brilliant diamonds. Oval shape diamonds are more of elongated round diamonds while marquise cut diamonds are shaped like a boat with points at the ends. Both diamonds offer an exceptional value as they tend to cost less than the round cut diamond. Other shapes in the brilliant family of cuts include heart shapes, triangular or trillion cut and the pear shape diamond.
The next diamond cut is the rectangular cut corner step cut, or “emerald” shape. The square cut corner step cut is called the “Asscher” cut. Asscher and emerald cuts offer a very unique fire and scintillation and have been quite a popular choice for engagement jewelry in recent years. Related to this cut is the baguette cut diamond, more commonly used as accent diamond in jewelry.
Diamond Carat Weight
Diamonds are small and required a precise measurement system to accurately weigh them as the cost of a diamond is derived by its weight. In ancient times diamonds were weighed on counter balance scales with tiny carob seeds as the counter weight. Since carob seeds were uniform in shape it was assumed to be a fairly accurate means of weighing and pricing a diamond. Over time more precise measurement tools were invented but the unit of measurement for diamond carried the traditional name “carat”, after the ancient carob seeds. Today one metric carat is equal to a fifth of a gram and we now have sophisticated digital scales capable of weighing diamonds down to the thousandth of a carat and are so sensitive they have enclosed weighing trays to prevent subtle changes of air from affecting the reading.
Carat weight is also indicative of the visual size of a diamond, as diamond cuts evolved a correlation of the size and weight of a diamond became closely related. Now diamonds are cut to tolerances that the millimeter diameter of a stone can accurately determine its weight on a scale. A round brilliant diamond measuring 6.5 mm in diameter will weigh approximately 1 carat as a princess cut diamond measuring 5.5 mm by 5.5 mm will weight approximately 1 carat.