Brilliant is a processed diamond with no less than 57 facets.

The History of Brilliants

Many legends and myths about brilliants have been created, starting from snakes guarding the diamond valley to powers given by the mysterious brilliants.
The brilliants were first mentioned in written sources approximately 3000 years ago in India, where they were valued for their property to split light.
Brilliants were used for medical purposes during the Middle Ages. This was the reason why pope Clementine had an unsuccessful treatment with brilliants in the early Middle Ages. Due to the discovery of large diamonds, e.g. “The Blue Hope”, the popularity of brilliants has increased during the Middle Ages.
Later on, a greater attention was set on the value of the diamond rather than on its mystical powers. In order to protect the mines from theft, their owners spread rumours, that the unprocessed diamonds were poisonous.
Nowadays, brilliants are used as gemstones for jewellery or as good luck charms holding mystical powers.
India remains one of the leading countries in diamond processing to this day.  

There are four criteria of the assessment of the brilliant – a classification of 4C’s: Cut (cutting, grinding), Clarity (Clarity, shape), Colour (Colour), Carat (weight, carats).
Each stone is compared to a benchmark and a respective index is obtained.
According to the American scale, the colour of the brilliant is expressed in letters, and according to the Russian scale – in numbers from 1 to 9. The greater the number, the darker the stone is.

Cutting is a characteristic including the proportions of the brilliant, the quality of facets, etc. The quality of the cutting of the brilliant determines such properties as sparkle quite a bit.
Depending on the skill, brilliants can be cut in various shapes. Each shape is created to highlight the specific characteristics of the brilliant. The optimal number of facets is 57, however, before the jeweller can start grinding, he must give the brilliant a geometrically correct shape - round, oval or pear.  
The sparkling of the stone depends on the quality of grinding. A round stone mostly highlights the advantages of the diamond and a rectangle or oval shape reduces the amount of reflected light. Respectively, a round brilliant is more expensive by 30-50 %.  

Facet count and names

The modern round brilliant (Figure 1 and 2) consists of 58 facets (or 57 if the culet is excluded); 33 on the crown (the top half above the middle or girdle of the stone) and 25 on the pavilion (the lower half below the girdle). The girdle may be frosted, polished smooth, or faceted. In recent decades, most girdles are faceted; many have 32, 64, 80, or 96 facets; these facets are excluded from the total facet count. Likewise, some diamonds may have small extra facets on the crown or pavilion that were created to remove surface imperfections during the diemond cutting process. Depending on their size and location, they may hurt the symmetry of the cut and are therefore considered during cut grading.
Figure 1 assumes that the "thick part of the girdle" is the same thickness at all 16 "thick parts". It does not consider the effects of indexed upper girdle facets. Figure 2 is adapted from the Tolkowsky book, which was originally published in 1919. Since 1919, the lower girdle facets have become longer. As a result, the pavilion main facets have become narrower.

Traditional Forms of Brilliants:
·         Round – a round brilliant consisting of 57 or 58 facets.
·         Oval – of oval shape
·         Marquise – Oval shape, with tapered ends. A shape created by the order of King Ludwig XIV to Marquise de Pompadour
·         Pear – of pear shape
·         Emerald – of a rectangular shape
·         Princess – of a square shape
·         Radiant – of a square or rectangular shape with cut edges
·         Asscher – of a octagon shape

Other fancy shapes of brilliants:
·         Heart – of a heart shape
·         Butterfly – of a butterfly shape
·         21Cn – 21st century, etc.

Almost all brilliants have natural cracks, impurities, which worsen its transparency and sparkle at the same time. The main criterion of the quality of the brilliant is the level of its clarity (size of the blemishes), which is determined by a special scale. If we would put a needle through a paper and would divide the hole in 4 pieces, we would obtain an inclusion marked by number two. The greater the number, the more visible the defect is. The clarity of the brilliants must be determined with a 10x magnification. 
According to Diamond High Council (HRD), the brilliants are classified based on their clarity:
·         LC – a completely clear brilliant.
·         VVS1/VVS2 (very very slight included) – cracks, inclusions, air bubbles, which can only be seen under a 10x magnification and only by a skilled gemmologist.
·         VS1/VS2 (Very slight included) – defects visible under a 10x magnification, though not visible to the unaided eye. 
·         SI1/SI2 (Slight included) – only an experienced gemmologist can spot the defects with a naked eye.
·         P1/P2/P3 – clearly visible defects noticeable by anyone.


The colour of the brilliant can range from completely colourless to yellow or brown.
Brownish and bluish stones can also found. However, completely transparent and defect-free gemstones are valued the most. There are also brilliants of fancy colours. M/Z are not fancy coloured diamonds, though some might think otherwise.
The colour is graded with alphabetic letter from D to Z:

D/E/F - Colorless.

G/H - Near colorless.

I/J - Near colorless. Slightly tinted.

K/M - Faint yellow.

N/R - Very light yellow.

S/Z - Light yellow.

The weight of the brilliant is measured in carats (abbreviation ct.) (should not be confused with the purity of gold). One carat is equals to 0, 2 grams. The name is derived from the name of the carob (Ceratonia siliqua) seeds, because these seeds were used as weighs in the ancient days, and their weigh was very similar to approximately 0,2 gr.
The size of the natural diamonds varies. Large crystals weighing hundreds or even thousands of carats can be found among thousands of tiny grains. Large diamonds are rarely discovered.
Sometimes large diamonds have to be cut to smaller pieces, especially when obtaining smaller brilliants but of better quality (a greater sparkling and clarity is obtained).