Frequently Asked Questions
Q: What is Cut?
A: Diamond cutting is the art and science of creating a
gem-quality diamond out of mined rough. The cut of a diamond
describes the manner in which a diamond has been shaped and polished
from its beginning form as a rough stone to its final gem proportions.
The cut of a diamond describes the quality of workmanship and the angles
to which a diamond is cut. Often diamond cut is confused with "shape."
There are mathematical guidelines for the angles and length ratios at which the diamond is supposed to cut at in order to reflect the maximum amount of light. Round brilliant diamonds, the most common, are guided by these specific guidelines, though fancy cut stones are not able to be as accurately guided by mathematical specifics.
The techniques for cutting diamonds have been developed over hundreds of years, with perhaps the greatest achievements made in 1919 by mathematician and gem enthusiast Marcel Tolkowsky. He developed the round brilliant cut by calculating the ideal shape to return and scatter light when a diamond is viewed from above. The modern round brilliant has 57 facets (polished faces), counting 33 on the crown (the top half), and 24 on the pavilion (the lower half). The girdle is the thin middle part. The function of the crown is to diffuse light into various colors and the pavilion's function to reflect light back through the top of the diamond.
Q: What is Clarity?
A: Clarity is a measure of internal defects of a diamond
called inclusions. Inclusions may be crystals of a foreign
material or another diamond crystal, or structural imperfections such as
tiny cracks that can appear whitish or cloudy. The number, size, color,
relative location, orientation, and visibility of inclusions can all
affect the relative clarity of a diamond. The Gemological Institute of
America (GIA) and others have developed systems to grade clarity, which
are generally based on those inclusions which are visible to a trained
professional when a diamond is viewed from above, under 10x
magnification.
Diamonds become increasingly rare when considering higher clarity gradings. Only about 20 percent of all diamonds mined have a clarity rating high enough for the diamond to be considered appropriate for use as a gemstone; the other 80 percent are relegated to industrial use. Of that top 20 percent, a significant portion contains a visible inclusion or inclusions. Those that do not have a visible inclusion are known as "eye-clean" and are preferred by most buyers, although visible inclusions can sometimes be hidden under the setting in a piece of jewelry.
Most inclusions present in gem-quality diamonds do not affect the diamonds' performance or structural integrity. However, large clouds can affect a diamond's ability to transmit and scatter light. Large cracks close to or breaking the surface may reduce a diamond's resistance to fracture.
Diamonds are graded by the major societies on a scale ranging from Flawless to Imperfect.
Q: What is Color?
A: A chemically pure and structurally perfect diamond is
perfectly transparent with no hue, or color. However, in reality
almost no gem-sized natural diamonds are absolutely perfect. The color
of a diamond may be affected by chemical impurities and/or structural
defects in the crystal lattice. Depending on the hue and intensity of a
diamond's coloration, a diamond's color can either detract from or
enhance its value. For example, most white diamonds are discounted in
price as more yellow hue is detectable, while intense pink or blue
diamonds (such as the Hope Diamond) can be dramatically more valuable.
Most diamonds used as gemstones are basically transparent with little tint, or white diamonds. The most common impurity, nitrogen, replaces a small proportion of carbon atoms in a diamond's structure and causes a yellowish to brownish tint. This effect is present in almost all white diamonds; in only the rarest diamonds is the coloration due to this effect undetectable. The GIA has developed a rating system for color in white diamonds, from "D" to "Z" (with D being "colorless" and Z having a bright yellow coloration), which has been widely adopted in the industry and is universally recognized, superseding several older systems once used in different countries. The system uses a benchmark set of either natural diamonds of known color grade, or precision-crafted cubic zirconia; test lighting conditions are also standardized and carefully controlled. Diamonds with higher color grades are rarer, in higher demand, and therefore more expensive, than lower color grades. Oddly enough, diamonds graded Z are also rare, and the bright yellow color is also highly valued. Diamonds graded D-F are considered "colorless", G-J are considered "near-colorless", K-M are "slightly colored". N-Y are usually appear light yellow or brown.
In contrast to yellow or brown hues, diamonds of other colors are much rarer and more valuable. While even a pale pink or blue hue may increase the value of a diamond, more intense coloration is usually considered more desirable and commands the highest prices. A variety of impurities and structural imperfections cause different colors in diamonds, including yellow, pink, blue, red, green, brown, and other hues. Diamonds with unusual or intense coloration are sometimes labeled "fancy" by the diamond industry. Intense yellow coloration is considered one of the fancy colors, and is separate from the color grades of white diamonds. Gemologists have developed rating systems for fancy colored diamonds, but they are not in common use because of the relative rarity of colored diamonds.