What Makes a Good Cut Diamond?

OK. So we are onto the next main diamond cut on the list: the Good cut diamond. For those who have been following discussions of the various diamond cuts, this might start to sound a bit repetitive. Whilst that is a legitimate consideration, when it comes to assessing the actual quality of a diamond cut, the proof, as they say, is in the pudding.

The question is, how do you identify it? How do you know which diamond cut is which, especially when selecting between near competitors in terms of cut and clarity. Hence this Education page. Here will outline the main features of a Good cut diamond, and help you, the potential customer decide correctly before making a purchase.

Overview of Diamond Cuts

As in any of our discussions of diamond cuts, we shall start with a quick overview of what is meant by the term cut in the diamond gemstone and jewellery world. If you are new to the world of diamond quality and classification, diamonds are ordered according to set criteria in terms of quality which corresponds to price.

Notable here is the 4Cs. The 4Cs measure the diamond’s carat, cut, clarity and colour. Each of these factors breakdown into various sub-components that are the subject of study in our other Education pages, which are you free to look at. Here will clear out the general confusion that people tend to bring into the question of diamond cuts, as it is an important starting point when it comes to understanding the difference between various diamond Cuts.

First is the meaning of the term ‘cut’. Generally, the term cut is often applied to distinct shapes in which diamonds, usually in the gemstone range when it comes to fine jewellery like engagement rings, are found. Notable diamond ‘cuts’ or shapes are princess cut, cushion cut, emerald cut, Asscher cut and so on. Note that the term cut at the end of each of these names does not actually refer to the cut of the stone, but to its outward shape.

Of course, the type of shape will come to have some effect on the nature and quality of the cut. This is why, the diamond cut grading that was talked about, tends to be limited to only a certain number of cuts or shapes. Notably the round and princess.

The point of confusion is on the type of faceting that the gemstone is subject to. In the world of diamonds, the dominant type of faceting or the way in which the diamond is cut to produce a distinct shape is the brilliant cut. This differs from the mixed, or step-cut type of faceting which is popular in the world of coloured gemstones like sapphires.

Diamond Cut Meaning

Right so we now come to the actual meaning of ‘cut’ with respect to the 4Cs, what we are getting at is a collection of factors that affect the design and craftsmanship of the diamond. One that builds on the other intrinsic features that are based on the other Cs.

The diamond Cut for example measures the proportions, symmetry, size of the facets and angles, depth of the stone, and the quality of the polishing. This translates into around seven key factors, which we have outlined in our discussion of Excellent cut diamonds. The key point to bear in mind is that when it comes to diamond cuts, a number of key factors are measured in combination to assess the overall visual quality of the gemstone. Which is dependent on three key factors. They are the diamond’s:

• Reflection

• Refraction

• Dispersion

The reflection is arguably the most notable visual quality of diamonds. Since the visual presence of the gemstone is a function of its ability to reflect light. A factor that is greatly dependent on the faceting of the stone, and overall the cut.

Refraction is a feature in relation to the interaction of light with various surfaces it comes into contact with, with respect to diamonds, which have a refractive index of 2.41, it corresponds to the degree to which light fans out in different directions producing a distinct visual effect.

Dispersion is an interesting visual phenomenon that occurs when light hits the diamond that splits apart into an array of colours that make up the rainbow. Known under the industry term fire, it is a key visual point in the diamond.

What Determines a Good Cut Diamond?

Right. Now armed with that knowledge we are in a better position to answer the question: what determines a Good cut diamond? If the reader has been following this discussion or is somewhat aware of diamond quality factors he/she will know that diamond cuts are grouped into four types. Going in descending order in terms of quality and value, we have the Excellent cut, Very Good Cut, Good Cut, Fair and Poor.

When it comes to picking a diamond for an engagement ring, for example, a Good cut diamond is a solid option. For it reflects a substantial amount of light in relation to the top two cuts in the range. And like the top contenders in the diamond cuts range, Good cut diamonds do feature a substantial amount of fire and brilliance, but not to the same extent as the premium ones, but these diamonds come with the advantage of being more affordable.

On the downside, there is a degree of light leakage that results from the somewhat weaker proportions, lower quality of faceting, and the lack of evenness of the diamond's girdle can all be found at varying degrees in Good cut diamonds. In case this sound off-putting, it is with good reason. As diamond cutters set a very high standard when it comes to the Excellent and Very Good cut stones. Nonetheless, the Good cut diamond remains a solid option, with its ability to capture incoming light reasonably well with limited levels of sparkle.

Should Engagement Ring Buyers Go for Good Cut Diamonds

Good cut diamonds can be seen as the healthy middle child of this group. Whilst it is not the worst, it is by far not the best. You see when it comes to diamond cuts and quality, the cut is generally considered the most important factor. Since the quality of the cut affects many different aspects of the gemstone, getting a top-quality cut is generally preferred, with compromises being permitted in other areas. Thus Good cut diamonds, despite being closer to the top, are not always the favoured option.

In terms of the total supply of gem-quality diamonds, only around a quarter of diamonds entering the market today fall into the Good cut range. This is due to the fact that the top Excellent and Very Good diamonds dominate the supply. Which might give potential diamond buyers some indication. Thus when picking a Good cut diamond, the main selling will have to be on the cost savings, which you can then direct towards getting a larger carat diamond with better VS1 or better clarity.