Centenary Diamond

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Dr. Shihaan M. Lariff

Origin of Name

The Centenary diamond gets its name from the centenary of the De Beers Consolidated Mines Ltd. celebrated on March 11, 1988. 1888 was the year the English entrepreneur Cecil Rhodes incorporated De Beers Consolidated Mines Ltd. The Centenary rough diamond was actually discovered on July 17, 1986, at the Premier diamond mines, but all those involved in the discovery were sworn to silence. The closely guarded secret of the De Beers Mining Company was unveiled to the world only on March 11, 1988, at a special banquet held to mark the centenary and attended by dignitaries of diamond-producing countries, and companies involved in various aspects of the diamond industry and trade. The Chairman of the company Mr. Julian Oglivie Thompson, who delivered the welcoming speech on this occasion, wanted to give an element of surprise to his distinguished audience, and reserved the disclosure of his well-guarded secret until the tail-end of his speech. Accordingly the final statement of his speech was, "We have recovered at the Premier Mine a rough diamond of 599 carats which is perfect in color - indeed it is one of the largest top-color diamonds ever found. Naturally it will be called the Centenary Diamond." The Chairman's closing remarks was greeted by a wild round of applause, and the rough diamond discovered in 1986 was christened the "Centenary Diamond". Not only was this an appropriate moment to reveal the long kept secret of the Company, but the name chosen for the new discovery was also the most appropriate.

© De Beers Group

Characteristics of diamond

The 599-carat top-color rough diamond is the 3rd-largest rough diamond ever recovered from the Premier Diamond Mine

The Centenary rough diamond discovered in the De Beers Premier Diamond Mine on July 17, 1986, using the latest electric X-ray imaging system, was a 599-carat top-color rough diamond, the third largest rough diamond ever recovered from the Premier Diamond Mine, after the 3106-carat Cullinan rough diamond discovered in 1905 and the 755-carat Golden Jubilee rough diamond discovered in 1985. As of year 1986, the 599-carat Centenary rough diamond was the 15th largest rough diamond ever discovered in the world. See table below :-

According to this table the Centenary diamond occupies the 17th position. However, two diamonds above this, were discovered after 1986. They are the Millennium star rough diamond discovered in 1990 and the Lesotho Promise discovered in 2006. If we subtract two positions the Centenary diamond at the time of discovery in 1986, would be the 15th-largest rough diamond ever discovered.

List of largest gem-quality rough diamonds discovered in the world as at year 2011

Name	Country of discovery	Year of discovery	Carat Weight	Color	Position
Cullinan	South Africa	1905	3,106	Colorless/White	1
Excelsior	South Africa	1893	995	Colorless /White	2
Star of Sierra Leone	Sierra Leone	1972	969.80	Colorless/White	3
Incomparable	Zaire	1984	890	Brownish-yellow	4
Great Mogul	India	1650	787	Colorless/White	5
Millennium Star	Zaire	1990	777	Colorless/White	6
Woyie River	Sierra Leone	1945	770	Colorless/White	7
Golden Jubilee	South Africa	1985	755	Yellowish-brown	8
President Vargas	Brazil	1938	726.60	Colorless/White	9
Jonker	South Africa	1934	726	Colorless/White	10
Jubilee-Reitz	South Africa	1895	650.80	Colorless/White	11
Unnamed	South Africa	1984	620.14		12
Sefadu	Sierra Leone	1970	620	Colorless/White	13
Kimberley Octahedral	South Africa	1964	616	Yellow	14
Lesotho Promise	Lesotho	2006	603	Colorless/White	15
Lesotho Brown	Lesotho	1967	601	Brown	16
Centenary	South Africa	1986	599	Colorless/White	17
De Grisogono	Central Africa	Probably in the 1950s	587	Black	18
Letseng Star	Lesotho	2011	553	Colorless/White	19
Unnamed Petra Diamond	South Africa	2009	507	Colorless/White	20
Letseng Legacy	Lesotho	2007	493	Colorless/White	21
Light of Letseng	Lesotho	2008	478	Colorless/White	22
Jacob-Victoria	South Africa	1884	457.50	Colorless/White	23
Zale light of peace	Sierra Leone	1969	435	Colorless/white	24
De Beers	South Africa	1888	428.50	Yellow	25
Niarchos	South Africa	1954	426.50	Colorless/White	26

©internetstones.com

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Characteristics of the rough diamond

The Centenary Rough Diamond

The Centenary diamond was a 599-carat top-color rough diamond. In it's rough form the Centenary diamond resembled an irregular match box with angular planes, a prominent horn like structure jutting out at one corner and a deep concave on the largest flat surface. Thus the shape of the stone itself presented some serious problems to any experienced cutter who would attempt to cut it.

Gabi Tolkowsky examining the rough Centenary diamond

 

The 4Cs of the cut and polished diamond

The cut and polished Centenary diamond is a 273.85-carat, D-color diamond with a modified heart-shape. The unique feature of the stone is it's exceptional clarity, and the stone has been graded as internally flawless (IF). The dimensions of the diamond are 50.50 x 39.90 x 24.55 mm. The stone has a total of 247 facets, 164 on the crown and the pavilion, and 83 around the girdle.

 

The Centenary Diamond is a Type IIa diamond

The Centenary diamond, being a D-color diamond is a Type IIa diamond, free of nitrogen and all other chemical impurities. They are also structurally perfect diamonds, without any plastic distortions. Thus factors that usually cause color in diamonds are absent, and therefore these diamonds are absolutely colorless. The diamonds are said to be chemically pure and structurally prefect. However, they constitute only about 1-2 % of all naturally occurring diamonds.

 

The Centenary diamond is perhaps the largest faceted D-color internally and externally flawless diamond in the world

The Centenary diamond is perhaps the largest, faceted, D-color, internally as well as externlly flawless diamond in the world. The veracity of this statement is subject to the assumption that the Cullinan I and II diamonds,which are above the Centenary diamond in the table below, are not internally flawless, being true. The clarity of Cullinan I and II diamonds are not known exactly, and most of the literature available on the Cullinan diamonds mention only about the remarkable clarity of the Cullinan rough diamond before cutting, and the black spot in the middle of the diamond. Unfortunately, the clarity grades of the Cullinan satellite diamonds after cutting, seem to have been overlooked by all the available literature, and hence the use of the word "perhaps" to qualify the above statement.

 

The Centenary diamond is undoubtedly the 3rd-largest faceted D-color diamond in the world

According to the list of famous D-color diamonds given below, the Centenary diamond is undoubtedly the 3rd-largest, faceted, D-color diamond in the world. It is also the largest modified-heart shaped diamond in the world, and perhaps the only modified heart-shaped diamond in the list of famous diamonds greater than 100 carats in weight. See the second table given below.

 

List of famous D-color diamonds over 100 carats in weight

S/N	Name	Carat Weight	Shape/Cut
1	Cullinan I	530.20	pear
2	Cullinan II	317.40	cushion
3	Centenary	273.85	modified heart
4	Jubilee	245.35	cushion
5	Millennium Star	203.04	pear
6	La Luna	200.07	heart
7	Orlov	189.62	rose
8	Jacob-Victoria	184.50	oval
9	Regent	140.64	cushion
10	Paragon	137.82	7-sided
11	Premier Rose	137.02	pear
12	Queen of Holland	135.92	cushion
13	Zale Light of Peace	130.27	Pear
14	Niarchos	128.25	Pear
15	Portuguese	127.02	asscher
16	Jonker	125.35	emerald
17	Al-Nader	115.83	pear
18	Taj-i-Mah	115.06	moghul
19	Edna Star	115.00	emerald
20	Koh-i-Nur	108.93	oval
21	Mouawad Magic	108.81	emerald
22	Cartier	107.07	pear
23	Star of Egypt	105.51	emerald
24	Mouawad Splendor	101.84	pear
25	Star of America	100.57	asscher
26	Star of Happiness	100.36	radiant
27	Star of the Season	100.10	pea

©internetstones.com

The Centenary diamond is perhaps the 7th-largest faceted diamond in the world

The following table is a "comprehensive" list of 68 known faceted famous diamonds in the world greater than 100 carats arranged in descending order of weights. The table was painstakingly collated by our staff after collecting all available information. The list may not be entirely comprehensive as some diamonds might have been inadvertently omitted or due to lack of precise information. We have tried our best to make the list all inclusive. The list will be revised as more information on other new diamonds are received.

According to this list, the 273.85-carat Centenary diamond occupies the 7th-position, which means it is the 7th-largest faceted diamond in the world. The Centenary diamond comes immediately after the 312.24-carat Spirit of de Grisogono diamond, the 6th-largest diamond, and also the 2nd-largest black diamond in the world.

 

List of Famous Diamonds Greater than 100 carats in weight arranged in descending order of weights

S/N	Name	carat weight	shape/cut	color
1	Golden Jubilee	545.67	cushion	fancy yellow-brown
2	Cullinan I	530.20	pear	colorless/white
3	Unnamed Black Diamond	489.07	rectangular-cut	black
4	Incomparable	407.48	shield shaped	fancy brownish yellow
5	Cullinan II	317.40	cushion	colorless/white
6	Spirit of de Grisogono	312.24	old moghul-cut	black
7	Centenary	273.85	modified-heart	colorless/white
8	Oppenheimer	253.70	natural octahedral	yellow
9	Jubilee	245.35	cushion	colorless/white
10	De Beers	234.65	cushion	light yellow
11	Red Cross	205.07	cushion	canary yellow
12	Millennium Star	203.04	pear	colorless/white
13	Unnamed	200.87	pear	yellow
14	La Luna	200.07	heart-shaped	colorless/white
15	Orlov	189.62	rose-cut	colorless/white
16	Darya-i-Nur	186	table-cut	light pink
17	Jacob-Victoria	184.50	oval	colorless/white
18	Moon	183	round	pale yellow
19	Unnamed	180.85	briolette	yellow
20	Star of Peace	170.49	pear	brownish-yellow
21	Table of Islam	160.18	emerald-cut	black
22	Unnamed	150.00	emerald	yellow
23	Regent	140.64	cushion	colorless/white
24	Paragon	137.82	7-sided	colorless/white
25	Florentine	137.27	double rose-cut	light yellow
26	Premier Rose	137.02	pear	colorless/white
27	Algeiba Star	135.03	square-brilliant	yellow
28	Sarah	132.43	cushion	fancy vivid yellow
29	Golden Hue	132.42	cushion	yellow
30	Tiffany Yellow	128.54	cushion	canary yellow
31	Star of the South	128.48	cushion	fancy light pinkish-brown
32	Niarchos	128.25	pear	colorless/white
33	Portuguese	127.02	asscher	colorless/white
34	Jonker	125.35	emerald	colorless/white
35	Stewart	123.00	round-brilliant	yellow
36	Delaire Sunrise	118.08	square emerald-cut	fancy vivid yellow
37	Meister	118.00	cushion	yellow
38	Vainer Briolette	116.60	briolette	fancy light yellow
39	Hope of Africa	115.91	cushion	fancy vivid yellow
40	Al-Nader	115.83	pear	colorless/white
41	Gruosi Diamond	115.34	heart-shaped	black
42	Taj-i-Mah	115.06	moghul-cut	colorless/white
43	Edna Star	115.0	emerald	colorless/white
44	Unnamed	114.64	briolette	yellow
45	Unnamed	114.03	cushion	yellow
46	Mouna	112.50	cushion	fancy intense yellow
47	African Yellow	112.00		yellow
48	Earth Star	111.59	pear	brown
49	Cross of Asia	109.26	radiant	light brown
50	Koh-i-Noor	108.93	oval	colorless/white
51	Mouawad Magic	108.81	emerald	colorless/white
52	Anon	108.04	emerald	yellow
53	Rojtman	107.46	cushion	yellow
54	Cartier	107.07	pear	colorless/white
55	Golden Sun	105.54	emerald	yellow
56	Star of Egypt	105.51	emerald	colorless/white
57	Golden Door	104.95	pear	yellow
58	Geat Chrysanthemum	104.61	pear	fancy brown
59	Graff Constellation	102.79	round brilliant	colorless/white
60	Ashberg	102.48	cushion	dark orange yellow/amber
61	Mouawad Splendour	101.84	pear	colorless/white
62	The Alnatt	101.29	cushion	fancy vivid yellow
63	The Golden Star	101.28	cushion	fancy vivid yellow
64	Star of America	100.57	asscher	colorless/white
65	Sunrise	100.52	emerald	yellow
66	Star of Happiness	100.36	radiant	colorless/white
67	Star of the Season	100.10	pear	colorless/white
68	Graff Vivid Yellow	100.09	cushion	fancy vivid yellow

©internetstones.com

 

History

History of De Beers Consolidated Mines Ltd.

Discovery of diamonds in South Africa in the mid-1860s and the subsequent opening of the Kimberley and De Beers Mines

Diamonds were first discovered in Southern Africa in the mid-1860s on the farm belonging to Nicolas and Diederick de Beer, near what is now the city of Kimberly. Two diamond mines known as the Kimberley and the De Beers were opened on this farm, and eventually became the world's most productive diamond mines. The actual mining took place at a hill in the farm called Colesberg Kopple, where the miners dug intensively, along the course of a diamond bearing pipe (now known as Kimberlites). The Kimberley mine was named after the first Earl of Kimberley, who was then the British Colonial Secretary. The town of Kimberley was erected  in 1878, and incorporated into the Cape Colony in 1880.

Johannes Nicholas De Beer

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1868 Carte de Visite of Right Honourable John Wodehouse, 1st Earl of Kimberley - British Colonial Secretary from 1870 to 1874 and 1880-1882, after whom the town of Kimberley and the Kimberley Dimond Mine were named

Photo by - John Watkins

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A section of the Kimberley Mine in 1874

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Section of the De Beers Mine in 1874

Investment by the English Entrepreneur Cecil Rhodes in 1871, and the eventual acquisition of most of the diamond mines in South Africa. Incorporation of De Beers Consolidated Mines Ltd. on March 11, 1888

In 1871, the English entrepreneur Cecil Rhodes invested and obtained a claim in the De Beers mines. With the expansion of his investment Rhodes was eventually able to purchase most of the diamond mines in South Africa. On March 11, 1888, Rhodes incorporated De Beers Consolidated Mines Ltd. By mid 1890s, Rhodes had established the Diamond Syndicate with a view of controlling the word diamond distribution, in order to keep prices high and demand steady. The Diamond Syndicate was the forerunner of today's Central Selling Organization, that controls much of the world's trade in diamonds.

Cecil Rhodes founder of the De Beers Company and Prime Minister of the Cape Colony from 1890 to 1896

Ernest Oppenheimer, founder of Anglo-American Corporation of Namibia, becomes Chairman of De Beers Consolidated Mines Ltd. in 1929, leading to a partnership that explored the diamond mines of South Africa and Namibia and controlled the world diamond trade

In 1917, Ernest Oppenheimer founded the Anglo-American Corporation, which took control of the diamond mines in South-West Africa (Namibia), and created a new diamond syndicate. In 1926, Oppenheimer bought a seat on the De Beers board and became it's Chairman 3-years later. Since then De Beers Consolidated Mines Ltd. has been closely associated with the Anglo-American Corporation of South Africa, in exploring the diamond mines of Southern Africa and Namibia, and controlling the world diamond trade.

Sir Ernest Oppenheimer - Diamond and Gold Mining Entrepreneur who took control of De Beers in 1929

Discovery of the Premier diamond mine in Transvaal, South Africa 1902, where the world's largest diamond weighing 3,106 carats was discovered in 1905

Another important diamond mine, that was discovered in South Africa in 1902 by Sir Thomas Cullinan, was the Premier mine, situated in Transvaal, South Africa. It was in this mine the world's largest diamond weighing 3,106 carats in the rough state, was discovered in 1905, and was appropriately named the Cullinan Diamond. This massive colorless diamond was purchased by the Transvaal Government, and presented in 1907 to the reigning British Monarch, King Edward VII. Since then the Premier diamond mines has produced some outstanding diamonds such as the Niarchos in 1954, the Taylor-Burton in 1966, and the Premier Rose in 1978.

Sir Thomas Cullinan - Original Owner of the Premier Diamond Mine

De Beers Consolidated  Mines Ltd acquired a controlling interest in the Premier diamond mine in 1917, and later after World War II acquired the mine fully, beginning underground mining operations in 1945

The ownership of the Premier mines was subsequently acquired by the De Beers Consolidated  Mines Ltd. and under it's management became one of the most productive mines in the world. In 1917, De Beers Consolidated Mines that controlled several mines in the Kimberley region of Northern Cape Province of South Africa, acquired a controlling interest in the Premier Diamond Mine. Production at the Premier mine was disrupted during the outbreak of the 1918 worldwide flu pandemic, known as Spanish Flu. Production was again disrupted during the great depression of the 1930s and later the second World War. De Beers Consolidated acquired the mine fully in 1945, soon after World War II, and production resumed immediately afterwards. The mine which was operated hitherto as an open pit mine, now began underground mining operations, and under the management of De Beers Consolidated became one of the most productive mines in the world. The Premier mine is also the source of several high quality colored diamonds, including the very rare blue diamonds. The eleven exceptional quality blue diamonds that constituted the De Beers Company's limited edition Millennium Diamonds Collection, that was exhibited at the Millennium Dome, throughout the year 2000 were all sourced from the Premier diamond mines.

 

The Cutting and Polishing of the Centenary Diamond

De Beers Company commissioned a team of experts headed by Gabi Tolkowsky to evaluate the rough Centenary and recommend the most appropriate cut/cuts to be adopted

The next important step was the difficult task of cutting the rough centenary diamond to produce either a single faceted diamond or several smaller diamonds, keeping in mind the three cardinal principles of diamond cutting, viz. maximizing for brilliance, maximizing for color, and maximizing for yield. This required the skill and expertise of experienced and accomplished cutters in the diamond industry. The De Beers mining company commissioned a team of experts and world renowned master cutters, headed by Gabi Tolkowsky, a world renowned diamond cuter, hailing from a family of diamond cutters, with five new diamond cuts to his credit, to evaluate the rough Centenary, and to recommend the most appropriate techniques and designs, to be adopted, and subsequently to undertake the actual cutting of the stone. Others in the team included Geoff Woolett, Jim Nash, and Dawie du Pleiss, all accomplished diamond cutters.

 

Initial recommendation of the team of experts was to keep the rough diamond in tact to produce a single large modern-cut diamond and to remove the protruding horn, superficial cracks and flaws, before deciding on the actual shape/cut of the diamond

After a careful and extensive examination of the rough centenary using the most sophisticated electronic and other equipment at their disposal, the team recommended that the Centenary be kept in tact  to produce one single large modern-cut diamond. But, before the actual shape and design of the stone could be recommended, the team decided to eliminate the protruding horn, the large cracks at the edge of the stone, and other superficial flaws.

 

A specially designed room was created in the De Beers Diamond Research Laboratory in Johannesburg inside which the cutting and polishing of the diamond was to be carried out

A hand picked team of engineers, electricians, and security guards were also co-opted by the company to assist in this project. A specially designed underground room in the De Beers Diamond Research Laboratory in Johannesburg, was set up, with the sole purpose of working on the Centenary diamond. Design specifications for this room included the strength and stability of the materials used, in order to prevent mechanical vibrations and temperature variations, thereby minimizing any mitigating factor that might interfere with the cutting of the Centenary diamond.

 

Removal of cracked material and other superficial flaws was achieved by the traditional time-consuming method of hand kerfing,that resulted in a roughly egg-shaped stone

With everything in place, the team set about, with the difficult task of cutting the stone. The team decided not to use laser or saw for the initial steps of the cutting, to remove cracked material and other superficial defects. This was done to prevent the heating and vibrating of the diamond. Instead they adopted the traditional method of kerfing by hand, a process that is slow and time consuming. It took the team 154 days, to cut and remove 50 carats of cracked material. After this was completed they were left with a roughly egg-shaped stone weighing about 520 carats.

 

13 different designs that would suite the egg-shaped stone were presented to the De Beers board with a strong recommendation for one design the modified heart-shape which was accepted

Having successfully accomplished the initial steps in the cutting process, the team embarked on the difficult task of taking accurate measurements, and drawing appropriate designs, that may possibly suit the egg-shaped stone. The team finally presented 13 different designs to the De beers board, with a strong recommendation in respect of one design, viz. the modified heart-shape. The Board accepted the modified heart-shape as it's choice, and then the final process of faceting the Centenary began in March 1990.

 

The cutting and polishing of the diamond was completed in 10 months resulting in the breathtakingly beautiful, modified heart-shaped, internally flawless, 273.85-carat Centenary Diamond

The faceting was finally completed after nearly 10 months of painstaking work in February 1991. After  the completion of the cutting, the centenary diamond had a weight of 273.85 carats and dimensions of 39.90 × 50.50 × 24.55 mm. The diamond with the modified heart-shape had a record 247 facets, 164 on the crown and pavilion and 83 around it's girdle. This was the first time such a large number of facets had been created for a diamond, and the breathtaking effect of this was visible even to the casual observer. This was in line with Gabi Tolkowsky's belief that adding facets meant adding more mystery and reaction to the journey of light in the diamond. The GIA color grading  for the diamond is D-color, which is the highest grade for colorless diamonds, and the clarity is internally flawless (IF). In addition to the Centenary, two other flawless, pear-shaped smaller diamonds, weighing 1.47 and 1.41 carats were also cut from the rough.

Gabi Tolkowsky Examining the Centenary Diamond with a Jeweler's Loop

The value of the Centenary Diamond? Has the Centenary Diamond been disposed of by De Beers?

While the Centenary diamond has never been appraised for it's value, it is known to have been insured for around US$100 million, at the time of it's unveiling in May 1991. The stone was later loaned to the Tower of London, where it was displayed for a number of years. Whether De Beers still owns the Centenary, or whether the stone has been disposed of is still a mystery. Gabi Tolkowsky has said that he believes that the gem has been sold, but De beers declines any comment, citing it's policy of anonymity.

 

Reflections of the Legendary Master Diamond Cutter Gabi Tolkowsky from a lecture delivered to GIA students at the Carlsbad Campus in California

Gabi Tolkowsky was also involved in the cutting of the 755-carat Golden Jubilee rough diamond that metamorphosed into a beautiful, 545.67-carat, yellow brown, cushion-cut brilliant, the largest faceted diamond in the world

545.67-carat Golden Jubilee Diamond - the Largest Faceted Diamond in the World

Gabi Tolkowsky was also involved in the cutting of the 755-carat Golden Jubilee rough diamond, the large yellow brown diamond, also discovered in the Premier diamond mines in 1985, just one year before the discovery of the Centenary diamond. In fact it has been said that the Golden Jubilee rough was used by the De Beers Company, to test a series of modern tools and equipment developed by the company for the processing of larger diamonds. Not only did the tested equipment pass all the stringent conditions of the test, but the enormous rough diamond also metamorphosed into a beautiful, 545.67-carat, yellow brown, cushion-cut brilliant, taking the unique position held by the 530.20-carat Cullinan I diamond, as the largest faceted diamond in the world, a position which it held for over 80 years. After the success of the cutting of the Golden Jubilee, Gabi Tolkowsky and his team embarked on the more challenging task of cutting the Centenary diamond.

 

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Related :-

Golden Jubilee Diamond

Cullinan Diamond

Pink Sunrise Diamond

 

External Links :-

 

Legendary Master Diamond Cutter Gabi Tolkowsky Addresses GIA Students

References :-

1) Centenary diamond - From Wikpedia, the free encycllopedia

2) The Centenary - www.famousdiamonds.tripod.com

3) GIA Newsroom - Gabi Tolkowsky Addresses GIA students

4) Cecil Rhodes - From Wikipedia, the free encyclopedia

5) Sir Ernest Oppenheimer - From Wikipedia, the free encylopedia