Understand the cutting characteristics of gemstones is the most important and complex component of the Five Cs. When jewellers speak of the cut of a diamond, they are not referring to its shape. The shape is merely used to describe the physical characteristics of the diamond. The cut describes the level of precision achieved by the diamond cutter to form the desired shape. The diamond cutter’s level of training will dramatically influence the diamond’s brilliance, fire and sparkle. The precision in which your diamond is cut will determine its ultimate beauty. Diamond cutting is an art form that has the potential to release a magnificent fire from within the gem. Yet, the vast majority of diamond cutting grades are inflated to ‘Make the Sale’. Ensure that you trust the jeweller’s certification.
One in a thousand diamonds are cut by artisans who have spent countless hours perfecting the skills of strict proportions and faceting. When a diamond is cut to a superior proportion, light is reflected from one facet to another and then dispersed through the pavilion of the diamond and back through the crown. If the cut of the diamond is too deep, however, some light will escape through the opposite side of the pavilion. Conversely, if the cut is too shallow, light will escape through the pavilion before it can be reflected. When graded as fine, excellent or ideal cut, this quality of craftsmanship can add 15-40% to the value of the gem. Premium cutting is only considered in high colour high clarity gemstones.
Commonly diamonds cutters will cut their diamonds for economy. As in every other industry, price is generally important to the consumer. In diamonds, it is the cutter who largely controls the economy of the gem. As seen in the rough diamond diagram, the cutter has one limitation in the proportions – the width. Notice that there is plenty of depth. There is an enormous amount of pressure in all the cutting centres of the world to maximize the yield or weight.
Assume that the ideal diamond proportions should yield a .90 carat (90 pointer). The cutter realises that the retailer has far more calls for 1.00 carat diamonds than 90 pointers. In nearly all cases the cutter will alter the proportions to use up more depth and push the top corners out to create what is called a “lumpy” one carat diamond. To reduce costs further, minimal effort is used for symmetry to create any fire. The cheaper cut will sell quicker in most stores due to the fact that the diamond rough has attained the 1.0 carat weight. Under these circumstances the cutter and retailer will also rotate their inventory at a faster rate. In many of these sales, an accurate but lower cut grade is not given to the consumer for fear it will reduce its saleability.
If seeing is believing, just ask to see a selection of 90 pointers. Very few of these diamonds exist, and so the jeweller will often ‘move you up’ to a one carat, often of a lower quality. Generally, the 90 pointers offer exceptional value if they are well cut and are usually the same diameter as the lower quality 1.0 carat diamonds. The same scenario holds for (.48ct, 1.40ct, or 1.90ct).
For some consumers, identifying the cut grade may not be significant priority. And to be fair, for jewellery sales staff to explain the physics of light within a gem is far more complex than answering questions of colour and clarity. A common tendency is to state that all the diamonds are a “very good” cut. Do not assume that they are, however, unless accompanied by an Accredited certificate with your name on it. The average cut grade in the marketplace is fair to medium and fair to good. Be sure the cut grade is included with the colour and clarity analysis. If it is not shown, the cut grade will be near the bottom of the scale (if the jeweller is buying better cuts, the quality will always be indicated). To accurately explain relationships between cut grades, it is important to seek the assistance of a trained specialist. Gemmologists who maintain the highest level of ethics and integrity have attained the degree of Accredited CAP. In most cases their expertise will help provide the client with the best purchasing value.
Ask for the jeweller’s professional credentials. This vital information will indicate their expertise. Other professionals have their diplomas available to view – expect it from your jeweller, or walk away!