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What Facets On A Brilliant Cut Are Octagon?

Diamonds are cut and with respect to symmetry, proportion and depth, and then polished, into various ‘diamond cuts’. 

Over the years, diamond cutters have developed various cuts into which diamond stones have been shaped. These cuts are always with respect to the shape and size of the crystal from which the stone is being cut.

In recent times diamond cutters have been able to come up with very innovative ‘diamond cuts’ in addition to those that existed in times past. This is because they have been able to harness the available technology for such purposes. Technologies such as computer-aided design, CAD and laser cutting are being employed in coming up with very innovative cuts. Currently, there exist dozens upon dozens of diamond cuts.

The Brilliant Cut

Brilliant cut diamond is the most popular diamond cut. It is also one of the first diamond cuts to be introduced. Basically, a brilliant cut diamond is characterised by having multiple facets. The presence of these multiple facets makes a brilliant cut diamond reflect light in various directions and thus reflect brilliantly.

The round brilliant is the most popular kind. It is round, and shaped in a way that makes it somewhat similar to a cone in look. Brilliant cuts have over the years been cut using various table size, culet size, crown height, as well as length and depth of the bottom of the diamond. Brilliant cut diamonds with large facets having different shapes and small culet are said to be the better kinds. Typically, a brilliant stone is supposed to have a table diameter which is composed of more than half of the entire girdle diameter (53-59%). The pavilion should also be considerably deep – consisting of about 40-43.4% of the girdle diameter. The crown height on the other hand, has to be smaller in comparison (10.5-19.2%).

Facets Of A Brilliant Cut Diamond.

A standard round brilliant cut diamond has 58 facets. In some, there are 57 facets. These facets consist of a table, crown facets, pavilion facets, and a culet.

Facets of a brilliant cut diamond that are octagon

Among all the facets of a brilliant cut diamond, the table and the culet are octagonal in shape.

  • The table facet 

The table facet is the largest facet on a cut diamond. The table size affects the diamond’s face up appearance. This is why special consideration is given to the angles in which the crowns and pavilion are inclined to it.

The table facet gathers light and directs it into the interior of the table.

  • Culet

This is the pointed area of the diamond where all the facets of the diamonds meet. It is the small point located at the bottom of the pavilion. A diamond can either have a pointed culet (57 facets) or a flat culet which serves as an additional facet (58 facets). When existent, the culet of a brilliant round cut diamond is observed as an octagon.

The measure of width of the facet of the culet is the culet size. A culet may be none existent as in the case of a 57 faceted stone or small. Other size variations of culets that are regarded are extremely large, very large, large, slightly large, and very small.

The diamond face-up appearance and patterning of a round brilliant stone may be badly affected if the culet is large. 

Other facets of a brilliant cut diamond.

The other facets of a brilliant cut diamond are mostly triangular shaped. They are as follows:

  • Crown facets

The crown facets are made up of three different kinds: the upper halves, the stars and the bezels. Traditionally, a brilliant stone will have 16 upper half facets, 8 star facets and 8 bezel facets. These crown facets work in harmonics to gather and disperse light and to create the typical light and dark light synchronisation often observed in round brilliant cut diamond stones. 

The crown height is always between 10.5 and 19.2%. It is angled between 25.5° and 41.1°. These majorly depend on the standards they were cut to conform to.

Crown angle measures the angle between the table plane and the bezel facet plane. When combined with the right pavilion angle and table percentage, a cut diamond with the right crown angle is expected to be very bright and brilliant.

Star facets are to be cut to accurate length. Facets that are too long or short may have a negative effect on the face-up appearance of the diamond. 

  • The pavilion facet

The pavilion consists of 16 lower girdle facets, 8 pavilion main facets and a culet which is not found in some diamonds of this cut. 

For a diamond to conform to standard, the pavilion depth must be between 40% and 43.2%.This depth percentage is measured from the culet to where the main facet of the pavilion and the girdle intersect. It is measured to the nearest 0.5%.

The pavilion angle is also to be considered when cutting a diamond piece. For a round brilliant cut stone, the average pavilion angle is 38.7-40.9° depending on the standard used. This angle is the angle between the table plane and the main facet plane of the pavilion. The pavilion angle must not be too steep. Dark areas are always noticed under the table of stones with steep pavilion angles.

  • The girdle

The girdle is the circumference of a round stone. It is that thin part of a diamond that divides the crown from the pavilion. This part of the diamond may be polished or left rough.

Brilliant cut diamonds usually have a faceted girdle, as the triangular shape into which the other facets close to it are angled will make it faceted rather than left perfectly round. 

The durability of a stone is affected by the thickness of the girdle.


The facets of a brilliant cut diamond that are octagon are the table and culet (if not pointed). The other facets include the crown, pavilion and girdle. The unique appearance of a diamond is as a result of all these facets cut on it.

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