NEED TO KNOW: DIAMOND CUT
Choosing the shape is one thing, but the diamond’s cut can make or break the quality and overall appeal. Differences in the cut will greatly impact the diamond’s value, sparkle and its aesthetics.
The cut is paramount when it comes to the diamond’s shape, be it emerald, brilliant round, princess or heart-shaped. The diamond’s beauty relies on the cut more so than any other characteristic.
When the diamond is shaped, expert cutters must balance the diamond’s optimal cut against the maximum yield, maintaining as much as possible the carat weight from the original rough stone. The challenge relies heavily on the skilled cutter to cut proportionate and precise angles, symmetrical and balanced facets, ultimately producing a polished beauty.
A well-cut diamond can create an absolutely stunning fire, sparkle and brilliance because it can reflect and refract light perfectly. The well-cut diamond can have a slightly lower colour and clarity, yet look exquisitely stunning.
A hundred of years has been poured into research and experimentation on how to produce the perfect cut and how light reflects and refracts within these stunningly beautiful gems. Thanks to technology combined with years of study, we can now maximise the diamond’s brilliance through precise cutting and measurements.
REFLECTION: THE MANY VARIETIES OF SPARKLE
Diamonds will not sparkle in the absence of light. So, to fully understand how cut affects the diamond, it would be helpful to understand how the key ingredient to a diamond’s sparkle behaves.
Dispersion, brilliance and scintillation, when used by jewellers, all relate to when the eyes can perceive when the light hits the diamond’s facets. Thus, how much fire, brilliance and sparkle you will see solely depends on the cut of the facets.
Commonly known as fire, dispersion typically appears as flashes of different rainbow colours. The light will be bounced off inside the diamond’s walls toward the centre. Then, it shoots back up through the crown. As the light exits the crown, the colour spectrum is visible because of the slightly bent light.
Diamond experts have long noted that more fire is produced with diamonds that have steep crown angles and smaller tables. In other words, the better the cut, the more fire will be visible to the naked eye.
The way this works is a little like a mirror. The wide table at the top of a diamond takes in natural light, which is then split apart into the full spectrum of colours. These rebound and reflect within the main body of the diamond before being projected upwards and out through the table, exiting once again as pure white light.
Scintillation is the intensity of the diamond’s glitter and twinkle as it moves. This is the manner by which light bounces off the facets when it is moved. A well-cut diamond reflects the light from every angle exuding a mesmerising sparkle we all know and love.
THE ANATOMY OF A DIAMOND
In cutting the perfect diamond, there are 6 essential parts that need to be considered. The most important parts are the depth, table and diameter. Determining the cut grade rests on the ratio between the diameter, table and depth.
A PRECISE ART: DIAMOND CUT GRADING
Compared with clarity and colour, a cut can be relatively tricky to grade, because the right proportions directly affect the ability of the diamond to reflect light and provide brilliance. A precise cut not only can emphasise colour and clarity but also can make a lightweight diamond appear larger.
The exact art of diamond cutting is getting the proportions right. Significantly missing a fraction of the proportion could drastically affect the diamond’s overall value. “Light leakage” could occur when facets are not properly aligned at the correct angles, whereby instead of being reflected out of the diamond’s top sections, the light instead is reflected out of the pavilion or culet. A dark centre or a dull stone will result from a single mistake.
A well-cut diamond is able to maximise the light that strikes the pavilion. The light should escape through the top sections, that is, the crown and table, providing an eye-catching balance of white and coloured light.
“Excellent” is given to the diamond with the highest grade as determined by the GIA, while “ideal” is used by the AGS. Basically, the grade slides from “Excellent” to “Poor”. I rarely stock diamonds that are any less than “Very Good”.
Poorly cut diamonds allow the light to escape to the side or at the culet, resulting in a diamond with relatively no sparkle, fire or brilliance. Since the diamond’s grade is fairly limited by its weight ratio, this cut has an extremely thick girdle, thus increasing total depth. Thus, the diameter is smaller compared with the indicated carat weight.
Similar to “Poor” grade, fairly cut diamonds also allow most of the light to exit through the sides and bottom of the diamond, offering little brilliance. Diamonds of this grade are fairly acceptable for .75 carats or for diamonds that act as side stones.
Included in the top 25%, good cut diamonds reflect most of the light entering the diamond, showcasing sparkle and brilliance at a lower price point. This grade is still an excellent value compared with higher-cut diamond grades.
This grade produces superior fire and brilliance, by properly reflecting the light entering the diamond through the table. This relatively appears much similar to the “Excellent” grade but at a fairly lower price point. “Very Good” grade diamonds fall to the top 15%.
As the name implies, these diamonds are exemplary pieces. Its facets exhibit a clear “hearts and arrows” arrangement. This cut reflects almost all of the natural light entering the diamond through the table, producing a stunningly beautiful sparkle.