Lareef A. Samad B.Sc (Hons)
The name "Guinea Star" appears to reflect not only the country of origin of the diamond, viz. Republic of Guinea in West Africa, a source of high quality, top-color diamonds, but also the rare top-color of the diamond, known as D-color, the highest color grading for white diamonds and perhaps also the high clarity grading of internally flawless (IF) of the diamond, and the rare modified shield-shaped cut of the diamond, a combination of rare characteristics embodied in the term "Star." The name "Star" has been used previously to indicate a combination of rare characteristics such as D-color, FL or IF color-grading and a perfect symmetrical cut as for example in the "Star of America diamond" (D-color, FL, Asscher-cut), "Star of Happiness diamond" (D-color, IF, Radiant-cut), and "Star of the Season diamond" (D-color, IF, pear-shaped) that set a world record in 1995 for the highest amount paid for a single diamond at any auction in the world .
Modified Shield-shaped Guinea Star diamond
The Guinea Star diamond is an 89.01-carat, D-color, flawless (FL) diamond with a rare modified shield-shaped cut. It is a combination of all these rare characteristics, that has made the "Guinea Star Diamond" one of most famous diamonds in the world.
Being D-color, which are absolutely colorless, the Guinea Star Diamond is undoubtedly a Type IIa diamond. It is Type II because it does not contain detectable quantities of nitrogen that can impart a yellow color to diamonds. In the absence of impurities such as nitrogen, boron, and hydrogen, that can impart color to diamonds, the Guinea Star is an absolutely colorless diamond. Such chemically pure and absolutely colorless diamonds are known as Type IIa diamonds, and constitute only about 1-2% of all naturally existing diamonds. They are sometimes referred to in superlatives as "whiter than white," "brighter than bright," "purer than pure," "diamonds of the purest water" etc.
The shield-shaped cut is a mixed cut incorporating both brilliant-cut and step-cut facets, like the trilliant-cut and the kite-shaped cut.
The shield-shaped cut has seven sides, two more than the five sides found in the somewhat similar kite-shaped cut. In the standard shield-shaped diamond, the two additional sides are situated on the two sides of the shield, and are the longest of the seven sides, followed by the two sides that meet at a point at the bottom
Standard Shield-shaped diamond
Modifications of the standard shield-shaped cuts include the ones in which the longest sides are the ones that meet at a point, like the kite, and the more flattened shield-shape as found in the Guinea Star diamond where the longest sides are again on the two sides.
A modified shield-shaped diamond in which the longest sides meet at a point like the kite
Flattened shield-shaped Guinea Star diamond
The Guinea Star diamond is seven sided. The two longest sides are situated on the two sides and are not the ones that meet at a point. The shield-shape is flattened because, the sides at the top are longer than usual and have a larger obtuse angle between them than the standard shield-shape.
The rough Guinea Star diamond that weighed 255.10 carats was discovered in the year 1986 in the Areodor Mine of the Republic of Guinea, and became at that time the largest rough diamond ever found in this West African country. This was just two years after mining operations began in the Areodor Mine in 1984, a joint venture of the Guinean Government and Areodor Holdings a western and Australian consortium, whose major shareholder was Bridge Oil of Sydney.
Diamonds were first discovered in Guinea in the year 1932 by an Irish prospector, R. Dermody, two years after diamond discoveries in Sierra Leone. These diamonds were mainly alluvial diamonds discovered from the alluvial beds of the River Makona in the Macenta district close to the border with Sierra Leone. The main secondary alluvial deposits are situated in the river beds of the Rivers Diani, Milo and Baoule in the prefectures of Kerouane, Kissidougou and Macenta. Subsequently other deposits were also discovered in the west of Guinea in the region of Kindia and Forecariah. The first kimberlite pipe was discovered in Guinea, in 1952, in the Kerouane area and later other kimberlite pipes were discovered also in the prefectures of Kerouane, Kissidougou and Macenta. Hence, in Guinea diamonds occur both in primary deposits (kimberlites) and secondary deposits (Alluvial deposits), but diamond production is mainly from the alluvial deposits. Diamonds produced are of good quality and most of the stones are of gem quality
Map of Guinea - from the CIA World Factbook 2002
Southeastern Guinea showing the prefectures of Kerouane, Kissidougou and Macenta.
Exploitation of diamond deposits in Guinea began during the French Colonial period, in 1935, in Baradou in the Diani Valley by a company known as "Societe Guineenne d'Exploitation Minieres". In 1953 another company known as "Miniere de Beyla" began the exploitation of the rich Bonodou deposit. A third company known as "BEKINIA" operated between 1956 and 1960, producing 1.28 million carats of diamond. In 1956 the diamond producing areas of Guinea were invaded by thousands of llegal artisanal miners expelled from Sierra Leone.
In 1958, after Guinea gained independence from France, all independent diamond licences were revoked, and a national mining company was formed known as "Entreprise Guineenne d'Exploitation du Diamant" with technical assistance from the Soviet Union. The company operated for 12 years between 1961 and 1973, but produced only 214,314 carats, much less than what was produced in the five-year period prior to independence by "BEKINA." The Soviets withdrew from the project in 1973. Between 1973 and 1978 most of the mining was conducted by illegal artisanal miners whose production was smuggled out of the country.
In 1978, the Guinean Government signed a joint venture agreement with a consortium of the London-based Industrial Diamond Company (IDC) and the Swiss-based Simonius Fischer. The new venture carried out exploration in the area of Gbenko, and when the initial results proved positive and attractive, Bridge Oil of Sydney, Australia was invited to join in to help finance a large scale project. This resulted in the formation of the joint-venture company Aredor-Guinea S.A. in July 1981, with 50% of the shares being held by the Government of Guinea and 50% by Aredor Holdings whose major shareholder was Bridge Oil, Sydney (79%), and the remaining 21% being held by IDC and Simonius Fischer. Mining at the Aredor site began in 1984, and by the beginning of 1985, Aredor-Guinea S.A. became the only legal diamond mining company in Guinea, after the expiry of licences of all other companies. Areodor-Guinea S.A. continued mining in the concession allocated to it spanning a distance of about 1000 km and covering the areas of Banankoro and Gbenko from 1984 to 1993, mining mainly the flats of the Baoule River.
In the areas outside the government concession artisanal mining was authorized by the Governement, between 1980 and 1984 under the supervision of an organization known as "Service National d'Exploitation du Diamant" (SNED), and during this period a total production of 160,850 carats was recorded. SNED was abolished in 1985, when Aredor-Guinea S.A. became the only legal diamond mining authority in Guinea. This again led to illegal artisanal mining whose production did not benefit the country as the diamonds produced were smuggled out of the country. The status quo prevailed until 1992, when production by Aredor-Guinea S.A. declined and the government again relaxed the restrictions on artisanal mining and issued permits for mining on one hectare parcels of land under supervision of the National Direction of Mines (DNM), subject to the payment of a fee and a guarantee deposit for environmental restoration. This time the strategy of the government appeared to be successful, and today artisanal and small scale mining is the most productive sector in diamond mining in Guinea, producing around 300,000 to 600,000 carats per year.
Production at the Aredor-Guinea S.A. mine since 1984 had been exceptional. Almost 95% of the production was gem-quality and more than 50% consisted of diamonds weighing between 2 and 10 carats. The rough Guinea Star diamond weighing 255.10 carats was discovered at the Aredor mines in 1986, and became the largest diamond discovered ever discovered in the Republic of Guinea. In 1987, another 143-carat diamond discovered from the mine, was sold for US$ 3.65 million.
Production at the Aredor-Guinea S.A. mine declined in the early 1990s and in 1993 the company ceased operations as continued operation of the mine was not economical. In 1996, First City Mining of Canada purchased the stakes of Bridge Oil of Sydney in the company, and the company then became known as Aredor-FCMC. 15% of the shares in Aredor-FCMC is held by the Government and 85% by the Canadian Company Trivalence Mining Corporation. The company operates in the same area as Aredor-Guinea S.A. and its annual production is between 12,000 to 38,000 carats per year. In the year 2003, Guinea exported 666,000 carats of diamonds, worth US$ 46.4 million, out of which the bulk of the production - 637,528 carats - was by Artisanal miners and the remaining 28,472 carats by Aredor-FCMC. Hence, the bulk of the diamond production today in Guinea is by the small scale artisanal miners, with the industrial scale producers such as Aredor-FCMC only making a marginal contribution to the annual production.
The 255-carat Guinea Star rough diamond, the largest rough diamond ever discovered in Guinea in the Aredor mines in 1986, was most probably sold by the Industrial Diamond Company (IDC) based in London one of the shareholders in the Aredor-Guinea S.A. IDC had an exclusive contract to market the production of the mines through its offices in London. IDC put up the rough diamond for auctions either through its offices in London or Antwerp. Among the prospective buyers who examined the rough diamond before the auctions was Diamantaire William Goldberg founder of the William Goldberg Diamond Corporation. Goldberg was convinced of the great potential hidden within the rough diamond, and went all out to bid for the diamond at the auctions. Eventually the hammer was brought down in favor of William Goldberg, who paid the highest price ever paid for a rough diamond at an auction, a fact that entered the Guiness Book of World Records.
The rough diamond was examined and studied extensively by master cutters of William Goldberg Diamond Corporation including Diamantaire Willam Goldberg himself. They were convinced that a substantial portion of the diamond has to be sacrificed in order to uphold the well known maxim of the corporation, "never maximize the weight of a stone at the expense of its beauty." Eventually, the rough diamond was cleaved into three pieces, a larger piece and two smaller pieces.
A careful study of the larger piece revealed, that the ideal shape/cut that would fit the larger piece, would be a modified shield-shaped cut, that would bring out the inherent beauty of the diamond. Accordingly, after months of cutting and polishing the master cutters of the company turned out a finished product, that was undoubtedly one of the most perfectly cut symmetrical modified shield-shaped diamonds in the world. The finished product had a weight of 89.01 carats, the largest finished diamond from the 255 carat rough. Two other smaller diamonds were also produced from the smaller pieces, an 8.23-carat pear-shaped diamond and a 5.03-carat heart-shaped diamond. All three diamonds were D-color and Flawless (FL), the highest clarity grade achieveable by a diamond. The elimination of 153 carats of the rough diamond by the master cutters, in producing 102 carats (89 + 8 + 5) of Flawless clarity grade finished product, is a testimony to the dedication of the master cutters of William Goldberg Diamond Corporation in upholding the set quality guidelines of the corporation.
Since its inception in 1973, William Goldberg Diamond Corporation earned a name for itself as a renowned high-end jewelry company specializing not only in the manufacture and sale of high-end diamond jewelry, but also the processing and selling of high-end large diamonds and fancy colored diamonds. Among some of the most notable diamonds that were processed by the master cutters of the company, include 137.02-carat, D-color, internally flawless, pear-shaped, Premier Rose diamond; the 102-carat, D-color, internally flawless, modern oval brilliant cut Beluga diamond; the 89-carat, D-color, flawless, shield-shaped Guinea Star diamond; the 75.51-carat Briolette Diamond, certified by the GIA as the largest briolette-shaped, flawless diamond graded by them; the 8.9-carat, oval-shaped, fancy vivid pink, Pink Muse diamond; the 5.54-carat, fancy vivid orange, cushion-shaped Pumpkin diamond, the largest fancy vivid orange diamond in the world and the 5.11-carat, fancy red, internally flawless, trilliant-cut, Red Shield diamond, which subsequently came to be known as the Moussaieff Red diamond, the largest red diamond in the world.
For more information on the William Goldberg Diamond Corporation and its founder Diamantaire William Goldberg, please go to our web page on the Blue Lili Diamond
The shield-shaped cut is not only a rare diamond cut but also a fairly ancient diamond cut. One of the ancient and famous diamonds of Indian origin, with a 14th-century provenance, that bears this cut, is the 57.14-carat (55.75 old carats) Sancy Diamond, aka the Great Sancy to distinguish it from the Little Sancy or Beau Sancy, a 34-carat pear-shaped diamond of 15th-century origin. Both Sancys get their name from their one time owner Nicholas Harlay de Sancy, a nobleman, financier, and diplomat of 16th-17th century France, and Superintendent of Finance to Henry IV from 1594 to 1599, who was also a collector, connoisseur and dealer of diamonds. The Sancy diamond is almost colorless with a very faint greenish-yellow tint. It is undoubtedly the most celebrated diamond in history, having passed through more countries, and affected more royal families than any other diamond in history. For more information on the Sancy Diamond, please go to our webpage on the Sancy Diamond.
The 57.14-carat Shield-shaped Sancy Diamond
Another historic 15th or 16th century diamond that bears the rare shield-shape is the pale-yellow Florentine diamond, another diamond of Indian origin, that became a family heirloom of the Dukes of Tuscany during the reign of Ferdinando I de Medici, the 3rd Grand Duke of Tuscany (1587-1609), and later entered the Hapsburgs Crown Jewels after the death of Gian Gastone in 1737, the last of the Grand Dukes of Tuscany from the Medici family. The Florentine Diamond is a 137.27-carat, pale-yellow, 9-sided, double rose-cut diamond, with a shield-shape and having 126 facets. For more information on the Florentine Diamond please go to our dedicated webpage on the Florentine Diamond.
Cubic Zirconium replica of the Florentine Diamond - a nine-sided shield-shaped diamond
You are welcome to discuss this post/related topics with Dr Shihaan and other experts from around the world in our FORUMS (forums.internetstones.com)
1) Diamonds in Africa - Republic of Guinea - Rafal Swiecki, www.minelinks.com
2) Facts About Guinea Diamonds - www.rothemcollection.com
3) In Pictures - Diamonds That Rock. Guinea Star, 89-carat shield. www.fobes.com
4) Famous Stones - Guineastar, 89 Carat Shield - www.williamgoldberg.com
5) Guinea Star - www.info-diamond.com
6) Guinea - From Wikipedia, the free encyclopedia
7) Diamond Clarity - From Wikipedia, the free encyclopedia
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