Parts of a Diamond: Culet

So we are on to the next key part of a cut diamond. One that is easily identifiable, but generally given less attention in relation to other parts that make up a top-quality carbon-based stone. We are of course talking about the diamond’s culet: for the unversed, this refers to the pointed tip at the end of the cut stone.

You know what it is. But how and why is this pointed end so significant? Well, that is the subject of this Education page. In which we will study this rather simple but structurally significant component that makes up the anatomy of a diamond.

Anatomy of a Diamond

As usual, we begin our analysis of the diamond culet with a quick overview of the key parts of the diamond. When speaking of diamonds in the gemstone and fine jewellery world we are invariably talking about a cut stone: that is a diamond which has been cut per specifications to meet gem-quality standards.

A stone that features a distinct shape (cushion, princess, halo), with designated cut (brilliant, step or mixed) and has been faceted in a way to meet the ideal, or falls closer to the deep or shallow cut levels. In other words, a diamond that is cut for use in gemstone jewellery is one that involves a great deal of intricacy, and hence each of its parts needs careful consideration.

The main parts of the diamond are the crown, table, girdle, pavilion and culet. Their particular shaping and the quality of the stone’s overall craftsmanship affect the cut quality of the stone. That is one of the elements that make up the 4Cs: With the cut, is generally considered the most significant.

We have so far engaged each of the other parts that make up the anatomy of diamond in dedicated Education pages. So you are free to look them up if want to. Here our focus is on the small but interesting culet, which plays an important role in determining diamond quality factors: fire, scintillation and brilliance.

What is a Diamond’s Culet?

The diamond’s culet is the tiny pointed end that you find at the end of a cut stone. The part where the downward-slopping pavilion meets as the united endpoint. And often the culet is a ‘point’: meaning that its distinct character, other than being the lowest point in a vertically standing cut diamond, it is also defined by its pin-like point. Diamonds which feature this type of culet are sometimes described as having ‘no’ culet. Though technically the pointed end does count as one.

As it happens the diamond's lowest point can feature a culet that does away with this pointed part. And instead features a flat surface. Which makes it technically a facet, that adds to the total facet count of the cut stone. For example, a round brilliant cut diamond that features a flat or non-pointed culet will add another facet. Increasing the total number of facets in the stone from 57 to 58.

The Importance of a Diamond Culet

At this point, the reader might be wondering what exactly is the point of having this, well, pointed culet. After all, the diamond or whatever gemstone is going to have an endpoint, and it could either be pointed or flat. This is a fair point. However, when it comes to diamonds, the visual character of the stone greatly depends on the structure and the quality of the faceting. For which the cutlet is of course of importance.

When it comes to assessing the importance of the culet, one must see it in light of the other parts of the cut diamond: since it lies at the end of the stone, it can be seen as the part which brings all other aspects of the stone together. A carefully structured diamond with a precisely angled pavilion and a well-aligned table will meet at the culet, which adds the finish to a well-cut stone.

However getting the culet right, can be trickier than simply having a pointed or flat end. This takes us to the next point on the various diamond culet grades.

The Eight Grades of a Diamond’s Culet

Not all cutlets have shaped the shape the way. We now know that diamond culets can either be pointed (none) or flat (facet). As it happens diamond culets are graded according to a certain gem quality standard set by the GIA in relation to their size. 

Here the reader needs to be careful, as even the pointed end of a cut diamond can also feature an area or tiny region that is visible to the naked eye, and certainly with the aid of various levels of magnification. This is interesting in that, whilst the endpoint of the diamond can technically be simply a pointed end, that end, depending on the cut of the stone and other stylistic factors can take up space.

According to diamond quality grading, the carbon based stone’s culet is rated in the following in accordance with the size of the (pointed) culet:

  • None: As the name implies in this the pavilion of the diamond is angled perfectly in a way to meet at the specific point. There is no in-between space. This a solid pointed end.

  • Very Small: A more favoured culet size, that is able to capture the unity and alignment found in the previous version, but with the added security.

  • Small: A more balanced but yet hardly detectable culet size. A solid option. But is visible with magnification.

  • Medium: The area of the culet is now starting to become more visible to the naked eye. But still not as prominent when viewed from the top. Remains a good choice. Though is better and resiting chips.

  • Slightly Large: A step above medium size, the culet is not big and not certainly visible, and exerts some effect on the appearance of the diamond which is slightly negatively affected by its presence.

  • Large: As the name indicates in this type of diamond cut, the pointed end is not exactly pointed: the culet size noticeably visible to the naked eye had some effect on the appearance of the stone.

  • Very Large: Now the culet size is becoming significant in that it now surpasses the 10 per cent threshold of the total diameter of the diamond. At this point the culet is significant and almost seems like a tiny facet. Whilst this size provides greater protection from chips it will affect the visual quality of the stone. And is visible from the top

  • Extremely large: The extremely large culet can almost be considered a facet, and is highly visible. Though more protective it negatively affects the visual quality of the cut diamond.

To Have or Not to Have a Culet?

This is one of those interesting questions in the diamond and diamond jewellery world where there is no clear answer. The first point of consideration is the visual character of the stone as it pertains to the fundamentals, that is 4Cs. Ensure that the diamond of your choice gets these other quality factors right: the colour, carat, and clarity.

The culet elements fall under the cut of the stone, and the presence of a pointed culet is a question of style, as they are considered the best in terms of allowing light refraction and the visual style of the stone, especially when viewed from the top. At the same time, a flat culet is a more secure option but comes at an increasingly lesser visual quality. The best approach is to strike a balance: with small to the medium being a solid range.

However when at this level (small to medium culet) there is still a risk of breakage or chipping. As the pointed end, even the most durable natural material on Earth is prone to breakage. Hence it is best to pick your ring style, in the case of a diamond engagement ring, that provides the kind of fit and security of the vulnerable end of the carbon stone.