Although natural carbon normally takes the form of graphite, the addition of tremendous heat and pressure force the carbon atoms to fall in line and a diamond is born. Transforming raw diamonds into works of art takes effort that only succeeds if the diamond has the right stuff to begin with. Four things to consider when determining if a diamond has been successfully transformed are cut, clarity, color, and carats.
Turning diamonds into real jewels starts with cleaving them by hand or with a high-speed rotary saw or laser to produce the desired size. Next, cutting the diamond into its final shape by hand is called bruiting while using a lathe is called cutting. Finally, powdered diamond abrasives are used to polish the finished stone. Most diamonds include a girdle that expands out past the top face to collect light and use refraction to direct it upwards where it combines with reflected light to give the diamond the quality of brilliance. In the process, the diamond acts like a prism to break the light into its spectral components. This quality is known as fire. A third quality, scintillation, is the sparkle created as light passing through the diamond is either refracted towards or away from the observer. Currently, the most popular type of cut for diamonds is the round brilliant cut. In side profile, this cut sports the recognizable diamond outline of a flat surface that quickly expands outward to the girdle before gradually drawing to a tapered point at the bottom. Looking at its face or table, the round brilliant features an octagon in the center surrounded by a series of various-sized triangles that create the appearance of overlapping crosses radiating out from it. This pattern best matches the diamond’s natural octahedral form and is used as the basis for more elaborate diamonds offering teardrop, pear, or heart shapes.
Diamonds are assessed on how free they are of either chemical impurities, structural distortions, or other inclusions. This scale assigns a grade of F, flawless, or IF, internally flawless, if the stone is completely free of imperfections. With microscopic flaws invisible to the naked eye, scores of VVS1 or VVS2 are given. If the inclusions are slightly bigger, the grades are VS1 or VS2. When imperfections are just perceptible, the diamond is assigned grades of SI1 or SI2. For the most obvious flaws, the diamond can receive either a score of I1, I2, or I3.
Ideally, perfectly crystallized carbon will have no color to it. Using this as the standard, the highest color rating for a diamond, a grade of D, indicates the diamond is completely clear or white with no impurities or structural alterations that distort its color. The rating scale for diamonds runs from D all the way down to Z. This scale only concerns the diamond’s color and diamonds possessing colors other than white are still often considered highly valuable as gemstones because of their beauty and rarity. Colored diamonds can result from the addition of non-carbon elements like nitrogen which gives diamonds either a yellow or brown appearance. The addition of boron creates shades of blue while hydrogen results in purple. There are even black diamonds caused by the introduction of graphite or sulfur into the mix. Other colors like green, red, and pink are the product of deformities in the diamond’s carbon matrix.
The final C, carat, refers to a measurement of weight that’s used for diamonds along with other gemstones. A carat is the equivalent of 200 milligrams, but this wasn’t always the case. Originally, this measurement derived its name and heft from the carob seed. Like the seeds, gemstone carats could vary dramatically. Just to get an idea, before the carat became standardized, it could range from 187mg for diamonds sold on the island of Cyprus in the eastern Mediterranean to 215mg for those originating out of Bucharest, Romania. In 1907, the fourth General Conference of the Metric Convention established the current internationally-accepted standard. This fixed weight is further subdivided into smaller units called points that are one-hundredth of a carat. When examining information regarding a specific diamond, the weight in carats is designated with the suffix ct.