BRILLIANT (from the French word "brillant" (lustrous) * EN: brilliant, diamond; DE: Brillant, Diamant; FR: brillant, diamant; ES: diamante; RU: бриллиант) is the faceted diamond of the jewellery quality; abroad, they understand as the brilliant the diamond, which is having the brilliant faceting. The first brilliants represented by themselves the diamonds with the naturally polished faces. The faceting of the diamonds within Europe has originated during the 14th century within Venice, the brilliant faceting has been invented within Flanders during the 15th century (see the details within the "Belgium" article).
There are the prototype for the brilliant faceting the natural crystals (octahedra and dodecahedra). There has got the greatest distribution the "rose" form of faceting (Figure # 1).
|(Table) The most known brilliants|
|Name||Mass, carats||Colour||The initial mass of the crystal, carats||The place of the find||The place of the storage|
|"Great Star of Africa" ("Cullinan I")||530.2||Colourless||3106.00||South Africa||Great Britain, London, Tower|
|"Lesser Star of Africa" ("Cullinan II")||317.4||-||-||South Africa||At the same place|
|"Nizam"||277.0||-||440.00||India||India, private collection|
|"Jubilee"||245.35||-||650.80||South Africa||USA, Washington, Smithsonian Institution|
|"Orlov"||189.62||-||300||India||USSR, Moscow, USSR Diamond Fund|
|"Victoria 1884"||184.5||-||469.0||South Africa||India, private collection|
|"Derianur" ("Iran")||176.00||Pink||Unknown||India||Pakistan, private collection|
|"Pink of the Queen Elizabeth"||23.60||-||54.0||Tanzania||USA, New York, private collection|
|"De Beers"||234.50||Yellow||428.50||South Africa||India, private collection|
|"Victoria 1880"||228.50||-||428.50||South Africa||India, private collection|
|"Red Cross"||205.00||-||375.00||South Africa||Switzerland, private collection|
|"Tiffany"||128.51||-||287.42||South Africa||USA, New York, the "Tiffany & Co" firm|
|"Earth Star"||111.59||Brown||248.90||South Africa||Not known|
|"Black Orlov" ("Eye of Brahma")||67.50||Black||-||India||USA, New York, private collection|
|"Hope"||45.52||Blue||110.50||India||USA, Washington, Smithsonian Institution|
|"Dresden Green"||41.00||Green||Unknown||India||East Germany, Dresden, Dresden palace|
The brilliants have been described for the first time by the jeweller Daniel de Hase during the 1614. Several brilliants are noted among the jewellery pieces of the English Queen Mary II (1668). During the 17th century, many of the stones, which have been previously faceted as the "baguette" and "rose" types, have been repeatedly faceted into the brilliants (for example, during the 1673, the King Louis XIV has ordered to change the faceting for the "Tavernier Blue" diamond, and to give to it the heart-alike shape, which was fashionable during that time; later, it has been repeatedly faceted yet another time, and is now known with the name of "Hope"). During the 18th century, there have got the distribution the brilliants of the square shape, which were having the "Peruzzi" faceting. The more recent "regent" faceting differs from the "Peruzzi" faceting by the more rounded corners. The mechanical grinding, which has been introduced into the diamond industry during the end of the 19th century, has led to the change for the proportions of the stone, and to the emergence of the modern round brilliant faceting (Figure # 2), which is revealing the light play and the lustre of the stone in the greatest manner. The "complete" brilliant faceting has 57 flat faces.
They distinguish the top (crown), middle (girdle), and bottom (pavilion) parts of the brilliant. The table (the top facet), which is is perpendicular to the axis of the brilliant, has the shape of the regular octagon. On the crown, except the table (the top facet), there are placed the 32 facets within the three belts. The middle part of the brilliant determines its shape and size; on the bottom part, there are situated 24 facets within the two belts, which are gathered together into the point, which is named the spike. In certain cases, instead of the spike, they create the plane, which is named the culet (it is situated parallel to the table (the top facet) at the top, and repeats its shape).
The sizes for the brilliants of the "complete" faceting, depending on their masses, are shown with their natural sizes on the Figure # 3.
The optimal geometry for the round brilliant (the ratio for the height of the crown, girdle, and pavilion, and also the diameters of the table (the top facet) at the top and of the plane of the girdle, the angles of inclination for the major facets of the crown and pavilion) has been calculated during the 1919 by Marcel Tolkowsky (the so-named ideal faceting by Tolkowsky). Within the industry, there is often used the so-named practical brilliant faceting, which is taking into account the real shape of the original crystal, and is permitting to use the raw materials in the optimal manner. The most distributed shapes for the faceting of the brilliants (Figure # 4) are: round (of the so named simple and complete faceting), fantasy ("pear", "marquis", "heart", "oval"), rectangular ("baguette", "emerald").
There is effective the "impariant" unpaired faceting, which is based on the odd symmetry of the brilliant (9, 11, 13, or 15 faces), or the profile faceting ("princess"), when there is assigned to the stone the plate shape with numerous grooves.
During the assessment for the value of the brilliant, there are taken into account the colour, "clarity" (the existence of the cracks, inclusions, defects, and so on), mass, and quality of faceting. For the classification of the brilliants according to the colour, there has been developed, and during the 1978 established, the International Colour Scale, which is based on the comparison of the brilliant with the collection of the samples, which have been selected as the colour standards by the leading gemologists of the world. Within the USSR, the brilliants are divided according to the colour, depending on the mass, into 4-9 groups. The defects of the brilliant are determined visually with the help of the ten-times (abroad) or six-times (within the USSR) magnifying lens. According to the classification, which has been established within the USSR, the brilliants are divided according to "clarity", depending on the mass, into 5-11 groups, while abroad the brilliants are divided according to these features into 7 groups. Within the international practice for the sales of the brilliants, there are widely used the certificates, which are given by the gemological institutes and laboratories for the stones with the mass of more than 0.5 carats. There are shown within the certificate the shape and type of the faceting for the brilliant, the dimensions (in millimetres), the mass (in carats), the proportions, the quality of the polishing, the symmetry of the stone, the degree of "clarity", the group of colouration, the luminescence under the UV light rays. The most known brilliants are shown within the Table and on the Figure # 5.
More than 95% of the worldwide production of the brilliants is accounted for the share of India, Israel, Belgium, the Republic of South Africa, and the USA. The first two countries process mostly small diamonds, the remaining countries issue mainly large brilliants. The worldwide capitalistic production of the faceted diamonds is 7.4 million carats (1979), including the share of India is 35%, of Israel is 29%, of Belgium is 20%, of the Republic of South Africa and of the USA is 7% each. The major centres for the faceting of diamonds into brilliants are: Surat (India), Ramat Gan (Israel), Antwerp (Belgium), Johannesburg (Republic of South Africa), New York (USA).
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