Incomparable Diamond

Origin of name

The name Incomparable was given to this diamond by its owners, the Zale Corporation, the Dallas based jewelry store chain, who purchased the enormous rough diamond from De Beers, and unveiled it to the world in November 1984, to coincide with the 75th anniversary of the Zale Corporaion. Perhaps the name seems to reflect the original intention of the owners of the diamond, to eventually transform it into the largest faceted diamond in the world, surpassing the 531-carat Cullinan I diamond, which had held the coveted position since 1908.

Characteristics of the diamond

The Incomparable diamond is a 407.48-carat, fancy brownish yellow diamond, with the highest clarity grade of internally flawless (IF). The cut of the diamond is described as a shield-shaped step cut. A new technical term coined by Mr. Marvin Samuels, a co-owner of the diamond, and head of the team of master-cutters who fashioned this unique diamond, describes the cut as a "triolette shape." The dimensions of the stone are 53.90 x 35.19 x 28.18 mm.

The Incomparable diamond is the 3rd largest faceted diamond in the world after the 545.67-carat Golden Jubilee diamond and the 530.20 Cullinan I diamond. It is also the largest faceted yellow diamond in the world. See table below.


List of famous yellow diamonds


Name carat weight shape/cut


1 Incomparable 407.48 shield shaped fancy brownish yellow
2 Oppenheimer 253.70 natural octahedral yellow
3 De Beers 234.65 cushion light yellow
4 Red Cross 205.07 cushion canary yellow
5 Florentine 137.27 double rose-cut light yellow
6 Sarah 132.43 cushion fancy vivid yellow
7 Tiffany Yellow 128.54


canary yellow
8 Vainer Briolette 116.60 briolette fancy light yellow
9 Mouna 112.50 cushion fancy intense yellow
10 Ashberg 102.48 cushion dark orange yellow
11 The Alnatt 101.29 cushion fancy vivid yellow
12 Walska 95.00 briolette yellow
13 Shah Diamond 88.70 table yellow
14 Porges 78.53 asscher fancy yellow
15 Victoria Transvaal 67.89 pear brownish yellow
16 Peacock 20.65 radiant fancy intense yellow
17 Shepard 18.30 cushion fancy intense yellow
18 Eureka 10.73 cushion brownish yellow



The  Incomparable diamond was discovered in the early 1980s, in the town of Mbugi Mayi, in the Democratic Republic of Congo (former Zaire). This is the same area where subsequently in the year 1990, the 777-carat rough stone that yielded the exceptional quality Millennium Star diamond was discovered.

In the rough state the diamond weighed 890 carats, making it the 4th largest gem-quality rough diamond to be discovered in the world. See table below.


List of largest gem-quality rough diamonds discovered in the world


Country of discovery Year of discovery Carat Weight


Cullinan South Africa 1905 3,106 1
Excelsior South Africa 1893 995 2
Star of Sierra Leone Sierra Leone 1972 969.80 3
Incomparable Zaire 1984 890 4
Great Mogul India 1650 787 5
Millennium Star Zaire 1990 777 6
Woyie River Sierra Leone 1945 770 7
Golden Jubilee South Africa 1985 755 8
President Vargas Brazil 1938 726.60 9
Jonker South Africa 1934 726 10
Jubilee-Reitz South Africa 1895 650.80 11
Unnamed South Africa 1984 620.14 12
Sefadu Sierra Leone 1970 620 13
Kimberley Octahedral South Africa   616 14
Lesotho Promise Lesotho 2006 603 15
Centenary South Africa 1986 599 16
De Grisogono Central Africa   587 17
Jacob-Victoria South Africa 1884 457.50 18
Zale light of peace Sierra Leone 1969 435 19
De Beers South Africa 1888 428.50 20
Niarchos South Africa 1954 426.50 21


The story of the accidental discovery of the diamond is quite interesting. A young girl was playing outside her uncle's house, where rubble from a nearby diamond mine had been dumped. The rubble had originated from old mine dumps from the nearby MIBA Diamond Mine. Mine dumps consist of soil and rubble that have already been screened for diamonds or have been rejected during the recovery process as being too bulky to be worth scanning for diamonds. The girl picked up an unusual stone from the rubble, perhaps out of curiosity and after playing with it for sometime gave it to her uncle, instead of throwing it back to where it belonged. After close examination her uncle realized that it was an unusually large diamond, and after confirming the stone was indeed a rough diamond, he sold it to some local African diamond dealers. The local diamond dealers carried the rough stone to Kinshasa, the capital city of Zaire, and met a group of Lebanese diamond dealers operating in the capital city. The Lebanese having examined the rough stone and being convinced of it's genuineness, purchased the rough stone from the African dealers for an undisclosed amount.

The Lebanese dealers carried the stone to Antwerp in Belgium, which is renowned as a global power house  in the diamond trade. It is estimated that 85 % of the world's rough diamonds and about 50 % of the world's polished diamonds, pass through Antwerp every year. At Antwerp, the unusually  large rough diamond was purchased by a senior buyer of the De Beers Company. The stone was then examined by Sir Phillip Oppenheimer, a Director of De Beers and President of the Central Selling Organization, a body that controls much of the world diamond trade. Mr. Oppenheimer was impressed by the enormous size and the color of the rough stone, but however decided to sell the diamond to Donald Zale, Chairman of the Board of the Zale Corporation, the Dallas based jewelry store chain. Donald Zale purchased the diamond in partnership with two other prominent diamond dealers of New York, Marvin Samuels of the Premier Gem Corporation, and Louis Glick. The enormous rough diamond was finally unveiled to the world, on the important occasion of the 75th anniversary of the Zale Corporation, that fell in November 1984. Thereafter, the rare and enormous rough diamond, was put on display at the Natural History Museum of the Smithsonian Institution, in Washington DC.

The next step was the difficult task of subjecting the stone to a detailed and exhaustive scrutiny, with a view of identifying any faults or inclusions that may exist, and recommending the most appropriate cut for the stone that would bring out it's hidden beauty. This was assigned to a team of  master cutters, supervised by Mr. Marvin Samuels, one of the co-owners of the stone, who had a wealth of experience in the faceting and polishing of large diamonds.

A careful examination of the stone revealed that the external structure and shape of he stone itself, would pose a serious challenge to any experienced cutter. The stone was highly irregular in shape, broader at one end and narrower at the other. The surface of the stone was quite rough with depressed and elevated areas, cavities and cracks. One side of the stone was sunken and pitted, and the other side was ridged. Having studied the stone externally, the team decided to have a closer look at the interior of the stone. This necessitated the opening up of a "window" on one side of the stone, as the general surface of the stone was completely opaque. The selected area of the stone was grounded to make a flat surface like a facet, and then thoroughly polished. This helped to open up the interior of the stone for closer inspection, and to everyone's great relief the interior of the stone appeared to be free of inclusions.

The owners and cutters of the rough diamond were then confronted with the same dilemma faced previously by owners of large diamonds like the Excelsior and Cullinan. Should they go in for a larger diamond with greater size and weight, that could be a challenge to the coveted position  held by Cullinan I,  as the largest faceted diamond in the world, or should they settle for several smaller diamonds of high quality, flawless and free of inclusions, that could be disposed of easily. In other words the choice was clear. One had to decide between size and quality. Most in the team favored the former, which would mean having a faceted stone exceeding the magic number 531 carats, which was the recorded weight of Cullinan I, the world's largest faceted diamond. But, as the work on the stone proceeded for the second successive year, it became apparent to Mr. Samuel and his team, that the idea of surpassing the weight of Cullinan I, has to be abandoned. Instead the team decided on a lesser option that combined both size and quality. Accordingly they decide to have one large stone, but not a big as Cullinan I, and several smaller or satellite stones, all of extremely high quality.

The rough stone was eventually sawn into one large piece and 14 smaller fragments. The team then decided that faceting of the smaller fragments should be completed first, before faceting of the largest piece. Mr. John Sampson White, the then curator of Mineralogy at the Smithsonian Institution, Washington DC, was then invited to come and have a look at the fragments of the rough stone. The most striking feature of the fragments that drew his immediate attention was the variation in color of the fragment, that he had not noticed before, when the stone was in one piece. Some fragments were rich yellow with a slight brown overtone, others were pale yellow, and the rest were almost colorless. The largest piece appeared to be of a medium yellow color, after the removal of the fragments. Being an expert mineralogist Mr. Samson White immediately came to the conclusion that the rough diamond  had not been uniformly colored, but extra-ordinarily color-zoned, i. e. the crystal had been composed of sharply defined areas of differing colors. Each of the color zones, represented a change in the environment that must have occurred as the crystal was building up. The stone must have been colorless at one stage, then a zone of pale yellow diamond would have been added, followed by a thinner layer of brownish yellow or amber colored diamond. When the initial fragments of the rough stone were cut the brownish yellow or amber-colored zone, that constituted only a part of the crystal surface was removed, leaving only a medium yellow colored stone. Fourteen satellite gems were cut from the fragments, the largest being cut in the shape of a kite, weighing 15.66 carats. The other 13 diamonds were of different shapes and sizes, varying in weight from 1.33 carats to 6.01 carats.

When faceting of the largest piece of rough stone was completed, it yielded a diamond weighing 407.48 carats, making it the second largest faceted diamond in the world, after Cullinan I (530.20 carats). This was no small consolation for the owners of the diamond, who had ambitious plans of transforming the rough into the world's largest faceted diamond. But, the Incomparable diamond could not hold on to this prestigious second position for long, because a rough yellowish brown diamond discovered in the Premier diamond mines in 1985, was fashioned into a cushion-cut diamond weighing 545.67 carats, making it the world's largest faceted diamond. This diamond eventually came to be known as the Golden Jubilee diamond, when it was presented to the King of Thailand by his loyal subjects, to mark the 50th anniversary of his coronation in 1997.

On October 19th, 1988, the Incomparable diamond was put up for sale at an auction held in New York. This was supposed to be the first time that such a large diamond was offered for sale at a public auction. The reserve price of the stone was placed at $ 20 million, but the highest bid obtained for the stone was only $ 12 million. Therefore the stone had to be withdrawn from the sale. Even the highest bid of $12 million made by the late Theodore Horvitz of Geneva, goes on record as the highest price ever bid  at an auction for a singe stone.

In November. 2002, the Incomparable diamond made an unusual appearance on the internet auction site EBay. A reserve price of £ 15 million sterling was placed on the stone, but the stone remained unsold as the auction time ran out.



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