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Understanding diamond-cut quality

diamond cut

When researching diamonds, potential buyers will inevitably come across the 4 C’s; namely colour, clarity, carat weight and cut. Understanding diamond-cut quality is extremely important. The cut of a diamond can refer to two different aspects of the stone, these are the style or shape, it is cut in, and the quality of its cut. Let’s have a closer look at the latter to see how one should take this into account when buying a diamond.

How do I know if a diamond is well-cut?

When referring to a diamond’s cut grade, a scale of specific terms is used to describe the quality. “Excellent cut”, for example, refers to a stone in which the facets are angled in a way that allows optimal refraction of light. This makes for a more brilliant and sparklier stone.  “Very good” cut refers to near ideal proportions and “Good”, “Fair” and “Poor” speak of diminishing cut quality.  The cut grade of a diamond is stated on its laboratory certificate, often along with a detailed analysis of exact angles and depth percentages.

Why is it important for a consumer to know this?

The cut quality of a diamond not only affects the perceived brilliance (beauty) of a diamond but also its value. Knowing what to look for in certification, and the stone itself, means you’ll be sure to get what you are paying for.

When viewing a GIA issued laboratory certificate, be mindful of three aspects noted with the diamond’s specifications. These are cut quality, polish and symmetry. If a diamond has been awarded an excellent grading for each of these aspects, it is known as a triple excellent cut and is more valuable than a poorer cut specimen, even if the diamonds are identical in colour, clarity and carat weight.

Bear in mind that by far the most important aspect here is the cut grade. Polish and symmetry gradings are not nearly as influential on the stone’s appearance or price.

What if the diamond isn’t certified?

When there is no laboratory grading to guide you, some critical observation skills are essential. You have the right to investigate and measure any diamond before purchasing it, so feel free to ask your jeweller for a calliper. A round brilliant cut diamond weighting 0.50ct, for example, should have a diameter of or close to 5.20mm. If the stone you have in front of you measures smaller in diameter than this, it is a deep cut diamond, which means you are paying for size you can’t see from the top.

In extreme cases, a deep or shallow cut diamond completely fails to refract light the way it was intended to. This becomes evident when a stone appears to have a dark spot in its centre (called a fish-eye), or if you are able to see straight through the stone.

If in doubt, insist on certification or keep looking, because when it comes to purchasing a diamond, you deserve nothing but the best.

At Mark Solomon Jewellers our diamond selection is truly a cut above the rest. We carry the largest selection of loose diamonds and diamond engagement rings under one roof in South Africa, including over 1,500 GIA certified diamonds, all available to you at wholesale prices. Visit our showroom or contact our sales team for more information, or to select the diamond cut out for you.

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