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When it comes to finding the perfect diamond, most buyers are familiar with the four C’s; Cut, Color, Carat and Clarity. This is the most basic tick list and works as a great starting point for your research. It is an undisputed fact that the most important of the four C’s is the cut. The cut of a diamond has by far the biggest impact on the sparkle, brilliance, fire and overall beauty of a diamond.

The unsuspecting buyer may assume that a GIA cut grade of ‘Very Good’ is sufficient and I can understand why. We hail the GIA as one of the most respectable and experienced gem grading laboratories in the world who are often considered the gold standard of diamond grading. However, truly understanding these grades and how they present themselves in a diamond means looking at the bigger picture. The complexity of diamond cutting and the demand for carat weight yield means that the majority of diamonds on the market are not cut to optimise the unique optical qualities of a diamond, rather they are cut for weight and profit. The result is a market saturated with sub-par diamonds. Furthermore, the GIA grades do not extend into the higher echelons of diamond cutting.

0.91 ct G VS1 A CUT ABOVE® Hearts and Arrows Diamond

GIA Excellent Diamond from Whiteflash

If you are wondering whether a GIA ‘Excellent’ or ‘Very Good’ cut is for you, this article will take you through the differences between the two and suggest where your money is better spent.

Diamond Cut: What to Look For

Before we look at the differences between a Very Good and Excellent cut grades, it is helpful to lay out what we mean by ‘the cut’ and what experts and wise buyers should be looking at. The most significant optical terms are:

Brilliance – Brilliance is a term which describes brightness, or more specifically, the internal and external reflections of white light.

Fire – Fire is colored flashes that appear across a diamond. It is the result of white light is split/dispersed into a full spectrum of colors.

Pattern – The patterning is how the facets present light and dark areas and whether they are proportioned, balanced and equally dispersed. A specific example of patterning is Hearts and Arrows.

Scintillation – A blinking or twinkling effect that should be in equal size and distribution. It is the result of areas of light and dark within the diamond and gives a diamond its distinctive sparkle.

You will find various tables and percentages that suggest the best proportions for a round brilliant diamond. These are extremely helpful but it is important to remember that the most beautiful diamonds present all of these elements working together harmony. There are a range of proportions that fall within each GIA cut grade, so it is a case of determining which ones tick all the boxes.

When it comes to color, clarity and carat weight, there is room for personal preference. While colorless diamonds are typically the most sought after, many buyers genuinely prefer a warmer tone diamond such as a K grade. Similarly, some customers find themselves unable to spot inclusions, so they may opt for a lower clarity grade such as an SI1 – and why not? Provided it does not compromise the durability of your diamond, there is no point spending money on something that you cannot see. Carat weight entirely subjective. However, when it comes to the cut there is a general consensus that the best of the best cuts are worth the money. In my years of experience, I have never had a customer prefer a lower cut grade when comparing diamonds.

GIA Very Good Cut VS Excellent

The GIA defines a ‘Very Good’ cut as follows:

‘Very Good Cut Diamonds offer exceptional brilliance and fire. A large majority of the entering light reflects through the diamond’s table. To the naked eye, Very Good diamonds provide similar sparkle to those of Excellent grade’

The definition sounds positive enough leads many buyers into thinking that a Very Good cut will offer good value for money and a good-looking diamond.

Excellent cut diamonds are defined as:

‘Excellent Cut Diamonds provide the highest level of fire and brilliance. Because almost all of the incoming light is reflected through the table, the diamond radiates with magnificent sparkle.’

The wording here is significant; the GIA suggest that diamond with an ‘Excellent’ grade provide the ‘highest’ possible level of fire and brilliance. However, around 55% of all-round brilliant diamonds receive and ‘Excellent’ grade from the GIA yet experts agree that at least half of these diamonds (in fact up to 30% of them) would not be recommended. In my experience I have seen excellent grade diamonds with unacceptable proportions, depth, table, angles etc.

Both ‘Very Good’ and ‘Excellent’ graded diamonds make up a huge percentage of round brilliants available on the diamond market. In amongst these, there will of course be some beautiful gems, but rooting them out requires more information. A quality such as color can be graded by the GIA and there will be no dispute that it is accurate. The cut is a little more complicated.

You may find the ‘magic proportions’ or suggested proportions for a round brilliant diamond. These serve as a helpful guideline but in truth, a change in one factor will influence the overall balance of the diamond. For example, a diamond with a table of 51% will require difference pavilion and crown angles to receive an ‘Very Good’ cut grade that a diamond with a table of 53%.

This GIA booklet uses matrixes to show how the table, pavilion angles and crown angles work together. This demonstrates the scope for variance. In each matrix, the other proportion parameters are assumed constant (star length (55%), lower half length (80%), girdle thickness (3.0%), polish and/or symmetry (VG or EX), girdle min/max (THN-STK), culet size (NON-SML)). Variances in these would change the outcome of the matrix, and therefore the overall cut grade.

The Best Advice

It is easy to tell people to go for the best cut that their budget will allow, but with such disparity between diamonds with the same GIA cut grade, this is not the easiest advice to follow. Every percentage, every angle and every facet make a difference to the overall ‘picture’ of a diamond and to really get to grips with that you need extensive diamond knowledge.

However, there are some tangible solutions and tips that you can follow to make the best decisions for your diamonds.

Ask an expert. Over the years I have helped hundreds of buyers navigate their way through the complicated world of diamonds. Whether it’s a side by side comparison or just knowing where to start, I can help you make informed decisions about your diamond buying and ensure you are getting the best quality for the best price.

Use the HCA tool. The Holloway Cut Advisor is a free online tool that allows you to input the diamond specs and generate an overall score. It is a fairly rudimental tool and is not without its flaws, but it is a great way to narrow down large collections of diamonds and separate those that are worth a second look.

Consider special selections. The best diamond vendors will do the hard work for you. I have mentioned the A CUT ABOVE® super-ideal cut diamonds by Whiteflash, but did you know they also have a Premium Select category? These diamonds are GIA certified an exclusive to Whiteflash. They are analysed, vetted and verified to be the best performing GIA diamonds available. Unlike the average ‘Excellent’ or ‘Very Good’ cut diamond, these stones possess true hearts and arrows patterning and optical precision guaranteeing fantastic light performance. I would suggest also reading my Blue Nile Review and specifically their Astor Collection.

Richard Jenkins, The Diamond Guru

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