Diamond Cuts
Diamond cuts are an important part of determining a diamond’s value, many experts say that it is the most important aspect. When customers hear the term “diamond cuts” they usually think of the diamond shapes, but diamond cuts are actually referring to the symmetry, polish and proportioning of the gem. When a jeweler is discussing the cut of a diamond they are talking about the number of facets and the arrangement of the facet’s within the diamond. A higher quality cut will return more light back to the viewer, resulting in more sparkle and brilliance. Each diamond is unique, but a typical round brilliant diamond has 58 facets.
A quality diamond cut will ensure that the diamond has more brilliance and sparkle– the actual sparkle of the diamond is directly related to the quality of the diamond cuts. A poorly cut diamond may appear dull and lifeless, even if the stone has higher quality clarity, color and more carats. Additionally, a well cut diamond has the illusion of being larger than it really is.
Most diamonds have two sections: the upper part of the diamond is called the crown and it is located above the girdle; and the lower part of the diamond is call the pavilion and it is located below the girdle. The area where the diamond crown meets the diamond pavilion is called the girdle, this is the area where the ring setting holds to diamond in place. The diameter of the diamond is a measurement from one end of the girdle to another. The total depth of the diamond includes both the crown and the pavilion.
The most prominent facet of the diamond is the top, it is the largest cut and is called the table or the face of the diamond. There is also a smaller cut made at the bottom of the diamond (the bottom of the pavilion) that is called the culet. Although the culet is not as visible by the naked eye, it is a very important cut because it protects the diamond from chipping. Although the cutlet helps to prevent chipping, not all diamonds have a cutlet.
Generally, two main diamond cut features are considered: depth percentage and table percentage. Depth percentage measures the depth of the stone (from table to culet) as a percentage of the width of the stone. The depth percentage ranges for each shape vary slightly, but the optimal depth percentage for a round brilliant cut is between 58% and 62%. Table percentage is the width of the table as a percentage of the total width of the stone (the width of the girdle).
There are several aspects of diamond cuts that should be considered:
- Proportions- When looking at diamond cuts, the proportions are the relationship of the angles and measurements. When a diamond has good proportions, the light reflects from facet to facet, and then the light is directed through the top of the diamond to the viewer. A poor diamond cut will allow light to escape before it reaches the top of the diamond, which results in a reduction of the brilliance of the diamond, because less light is reflected. There are very specific proportions that are measured to determine the diamond cuts: the table percentage of the diameter, the star facet percentage of the crown, the girdle thickness, the crown angle, the crown height percentage of diameter, the pavilion angle, the pavilion depth percentage of diameter, the lower girdle facet percentage of pavilion depth, and the total depth percentage of the diameter.
- Symmetry- The symmetry of a diamond refers to shape and the placement of the facets. When a diamond’s symmetry is rated any flaws in the symmetry will be taken into account: extra facets and facets out of place, off center culets and tables, wavy girdles, the misalignment of crown and pavilion facets. A diamond with good symmetry has a balance when it is viewed from all angles. High quality symmetry is difficult to achieve, it can only be achieved by a highly-skilled gemologist and requires precision and attention to detail.
- Finish- A diamond’s final polish is the finish of the diamond. It is more of an aesthetic term referring to the diamond surface after it is cut and only slightly affects the value of the diamond. Most commercial diamonds are already polished before they are sold.
- Brightness/Brilliance- The brightness of a diamond refers to the reflexion of light, both externally and internally. The diamond’s brightness is directly affected by the proportions of the diamond.
- Fire/Dispersion- The term fire or dispersion refers to the white light being dispersed into spectral colors, resulting in flashes of color. As the light travels past the diamond’s surface it displays a show of colors as the white light bursts into colors.
- Scintillation- When the term scintillation is used it is referring specifically to the top of the diamond, the areas of dark and light that are seen. If a diamond has more scintillation, then will be more flashes of light as the diamond is moved around.
When a diamond is rated it is given a cut grade of excellent, very good, good, fair or poor based on the cut-grading system that has been established by the GIA for diamonds.
Really the most important aspect of choosing a diamond’s cut is: your preference. Look at how the diamond sparkles under different lighting, are you satisfied with the brilliance and shine? Be sure to view the diamond in different light settings, all jewelers have lights designed to emphasize the reflection and brilliance of the stone– so it is important to ask them to view the diamond in another room, away from the showroom lights.
Keep in mind that if you are purchasing a vintage engagement ring or an antique engagement ring, that the cut of an older diamond should not be rated by these standards. Techniques have improved over the years and tastes have changed, resulting in different ways of cutting diamonds and determining diamond cut quality. Older stones were cut by hand, resulting in small flaws and variations in the facets; whereas modern technology now allows diamonds to be cut with lasers, resulting in more precise cuts and higher standards. When considering the quality of an antique engagement ring, the older stones are a piece of art– they have a softer look and are very valuable because of the history and charm that they have.
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