A diamond’s quality is assessed not just by carat, colour and clarity but also by the cut. “People know very little about assessing the cut of a diamond, which affects the light return of the stone and hence makes it sparkle. Until all parameters and proportions are maintained perfectly while cutting and polishing, a diamond will not have the right light reflection and hence not be considered a quality diamond,” says Biren Jhaveri, manager, sourcing, and senior gemologist, Tanishq.
The good news is that all the information you need about a diamond is usually on the certificate you get with it. But you need to be able to interpret it easily too. “Remember, when you are talking about the cut, you are actually talking about the shape of the diamond. However, when you are asking how well a diamond has been cut, you are asking about the quality of the cut and not the shape,” he explains.
A diamond’s cut (not shape) is based on three factors: proportions, symmetry and polish. “The major components of any diamond, from top to bottom, are the crown, girdle and pavilion. The proportions of a diamond refer to the relationships between table size, crown angle and pavilion depth. A wide range of proportion combinations are possible, and these ultimately affect the stone’s interaction with light,” says Jhaveri. There are five ways to rate how well a diamond has been cut —excellent, very good, good, fair and poor. “If the certificate says ‘good’, please know that this is not the best way the diamond could have been cut. There are two higher levels than this,” says Jhaveri. If the proportion grade (cut grade) is excellent, then be assured that everything is okay as far as the cut is concerned. “The symmetry is the balance of the stone. There are badly cut stones where the table of the stone was supposed to be in the centre but is slightly off-centre. The crown and pavilion may not be aligned. But when the cut grade says excellent, it means all these parameters have been taken care of,” says Jhaveri.
Token: An engagement ring at Zoya by Tanishq
The certificate should also indicate whether the diamond is an original one or a man-made one.
For colour, the grades are from D to Z. “D indicates the diamond is exceptionally white. As you go from D towards Z, the diamond becomes yellow,” explains Jhaveri.
“Also, know that clarity does not mean that the diamond has no flaws. It refers to the relative absence or presence of inclusions (inside the stone) and blemishes (on the surface on the stone). There are 11 grades in clarity—from flawless to three levels of inclusions,” he explains.
The last parameter on the certificate indicates fluorescence. “This indicates that when a diamond is subjected to ultraviolet light, it absorbs light and glows blue. Ideally, a diamond should not fluoresce. Diamond with strong and medium fluoresce should be avoided but if a diamond has mild fluoresce it will not affect its beauty,” he says.
— Seema Chowdhry