Jonker Diamond

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Origin of name

The Jonker diamond gets its name from Johannes Jacobus Jonker, the poor diamond digger in whose claim at Elandsfontein, about 5 Km south of the Premier mine, the diamond was discovered on January 17th 1934.


Characteristics of the diamond

The original rough Jonker diamond which weighed 726 carats was cut into 13 pieces, and eventually transformed into 13 diamonds of which the largest diamond weighing 142.90 carats retained the name Jonker. It was an emerald-cut, D-color diamond, with 66 facets. The stone was later re-cut to eliminate some flaws and improve it's brilliance. The re-cut stone, also an emerald-cut had 58 facets and weighed 125.35 carats. The Jonker I is one of the most perfectly cut diamonds in the world.

The Jonker diamond is perhaps the 16th largest, D-color diamond and the largest emerald-cut, D-color diamond in the world. See table below.


List of famous colorless diamonds greater than 100 carats in weight


Name Carat Weight


1 Cullinan I 530.20 pear
2 CullinanII 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 pear



The rough Jonker diamond weighed 726 carats, and in 1934 became the 4th largest gem-quality rough diamond to be discovered in the world. However the discovery of the President Vargas in 1938, weighing 726.6 carats, pushed the Jonker to the fifth place. Today, the Jonker occupies the 10th place in the list of largest gem-quality rough diamonds 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 rough Jonker diamond had a slightly elongated shape, the greatest length being 63.5 mm and width 31.75 mm. The color of the stone was white and it's clarity exceptional, that it led diamond enthusiasts to speculate, that the Jonker may probably be a fragment of the larger Cullinan diamond which had almost the same characteristics  and was discovered just 5 Km away in the Premier, diamond mines, in Transvaal, South Africa. However this speculation was laid to rest, by careful examination of the Jonker and models and prototypes of the Cullinan, by experts in the field.

The story of the discovery of the Jonker diamond is very exciting and interesting. Johannes Jacobus Jonker was a 62-year old white South African settler, who had tried his luck at diamond digging for a long period of 18 years, but without any success.

Diamond digging and mining are two different processes. While diggers work at the surface, going down to perhaps 10-20 feet, miners go deep down, sometimes as deep as several thousand feet. While diggers look for alluvial deposits of diamonds on the surface, miners follow naturally formed diamond pipes or veins, such as Kimberlites and Lamproites, that can go down to several thousand feet below the surface. While the risk involved in digging is minimal, the risk involved in mining is very much greater, needing special safety precautions, to safeguard the life of the miners. While diamond digging can be undertaken by a single individual or a group of individuals, mining can be done only by  well established companies, having the necessary equipment and financial backing, to initiate and maintain such a difficult venture, and requires the employment of miners who should be provided with attractive salaries, and other benefits, during their active working life, and substantial retirement benefits in later life. While diamond miners are quite certain  of finding diamonds, as they follow the diamond pipes and veins, diamond diggers can never be sure of getting any tangible results in their ventures. This was the main reason why 18 years of continuous digging, by Johannes Jacobus Jonker did not yield any fruitful results. Finding a diamond of exceptional quality is purely a matter of chance, and depends on how lucky the digger is. This explains why diamond diggers are always a poor and frustrated lot.

But, this time around luck seems to have knocked at Mr. Jonker's door. He was working a claim, at  Elandsfontein, 4.8 Km south of the Premier mine and 40 Km east of Pretoria, the administrative capital of South Africa. Mr. Jonker was a father of seven children, and some of his sons use to assist him in the work of digging. January 17th,1934, was a rather cold and windy day. It had also rained heavily on that day, and Mr. Jonker decided to stay at home, instead of exposing himself to the elements, and falling sick. He had been running out of luck, and 18 years of digging had not yielded anything substantial. Mr. Jonker was feeling dejected and discouraged. Therefore he decided to send his son Gert, together with two of his native South African employees, to continue the digging operations on his claim. As they continued with their work, Johannes Makani, one of the native employees who was washing a bucketful of gravel, suddenly picked up something from the bucket. He quickly walked to the cleaning shed and scrubbed the object, which he had discovered, to remove the coating of mud and dirt surrounding it. Makani was overridden with joy and shouted, "Oh God. I have found it." He rushed to Gert Jonker, and showed him his find. Gert at first thought he was looking at a piece of glass, but when he realized it was a real diamond, he rushed to give the good news to his father. When he eventually found him he got a good berating from his father for riding recklessly. However, when Jacob Jonker realized that what was in his hand  was actually a diamond, he went down on his knees and thanked God.

Most of the members of the Jonker Household were still skeptical about the new find and doubted whether it was actually an authentic diamond, having never seen one as large as the one discovered. However the news of the discovery spread like wildfire in the surrounding village, and this brought unexpected security problems to the poor household. Mrs. Jonker especially would not take any chances, and as a security precaution she deposited the diamond inside a stocking, and tied it around her neck. That night she went to bed, but never managed to fall asleep. Armed men with loaded revolvers kept guard at the entrance to the poor hut, to keep any would be attackers at bay.

Unexpected luck and prosperity to a poor household, can also bring it's fair share of problems, hitherto non-existent. While previously the family had reconciled themselves to their poverty stricken status, and had complete peace of mind, the sudden windfall had shattered that peace and tranquility and instead generated worries and tensions. However one of their initial worries of providing adequate security for the stone, was short-lived, as finding a suitable buyer was not a difficult task, as there were so many of them representing a multitude of famous diamond companies around the world, operating in the alluvial diamond fields of South Africa. The Jonker diamond was purchased by Mr. Joseph Bastiaenen, agent for the Diamond Corporation Ltd. belonging to Sir Ernest Oppenheimer, in the face of stiff competition from buyers representing other companies. The exact amount paid for the diamond was not disclosed, but was put at somewhere between £61,000 and £ 75,000 sterling. This transaction also involved another large crystal weighing 281 carats, that was discovered a few days earlier in he same area about 100 meters from the spot, where the Jonker was discovered. This stone was called the Pohl, named after another diamond digger J. M. Pohl. However in spite of it's size and the fine white color the Pohl contained several imperfections, which was the cause for it's depressed value.

The worries of the Jonker family did not end with the sale of the diamond. Immediately after the sale, the tax authorities of the South African Government were tipped off, and they moved in quickly, demanding a third of the stone's value as taxes, from Mr. Jonker. This amount was suppose to include three different taxes- Income tax, super tax, and provincial tax. However, the Minister of mines ruled that whatever money was spent in the discovery of the stone, should be exempted from tax, and deducted from the purchase price. Accordingly the Jones family was requested to forward their claim for tax exemption. The following is a breakdown of the relief claimed by the Jonker family :-

           1. Cost of digging operations for 18 years    - £  14,755

           2. Cost of negotiating the sale                   - £    1,000

           3. Preliminary expenses                             - £    1,000

           4. Donations not specified                         - £    3,600

           5. Donations to churches                          - £       755

           6. Traveling expenses                              -  £      200

               Total                                                -  £  21,310

The assessors of the tax department rejected all the above claims except 1 and 6, but reduced the 1st claim from £ 14,755 to £ 2,000, and the 6th claim from £ 200 to £ 100. Thus Mr. Jonker was given a tax exemption of only £ 2,100. Disappointed by the assessors verdict , the Jonkers petitioned the House of Assembly, praying for the exemption requested, but this too was turned down.

Being a religious person Jacobus Jonker seems to have reconciled himself to his fate, and paid the taxes demanded, as it is said that he underlined in his Bible, Verse 1 of St. Luke, Chapter 2, which reads as follows :- "And it came to pass in those days, there went out a decree from Caesar Augustus, that all the world should be taxed.'

In retrospect, the taxing of the poor diamond digger, who lived in abject poverty for almost 18 years, without any form of assistance from the Government, seems to be morally unacceptable, judging by today's standards, where miners and mining companies in some countries, are given tax concessions and tax-free holidays in order to boost production.

The diamond crystal  Mr. Jonker discovered may have brought him wealth and fame, but it destroyed his peace of mind. Having paid the exorbitant tax demanded by the Government, Mr. Jonker bought a farm, some heads of cattle, and a limousine, with the remaining money. In spite of his apparent prosperity Mr. Jonker remained a simple countryman at heart, and was never able to cope with the high-spending life style of the society he was thrust into by a sudden and unexpected change in fortunes. This had a disastrous effect on his finances and within a few years all he had left were his memories and his good name. Fame and fortune seem to have forsaken him.

The Jonker diamond was shipped by ordinary registered mail to the Diamond Corporations offices in London, on Charterhouse Street. Later the Jonker was offered for sale through the De Beers Central Selling Organization, which under the guidance of Sir Ernest Oppenheimer, had superseded the old syndicate of diamond firms. Harry Winston, the New York based diamond dealer had shown an interest in purchasing the Jonker. In 1935, Harry Winston instructed Hugo Prins, a senior partner of the diamond brokering firm I. Henning & Co. to start negotiations with the Central Selling Organization, on the purchase of the Jonker diamond. After successful completion of the negotiations which lasted several weeks Mr. Winston purchased the Jonker for over £ 150,000. The Pohl diamond was again included in the sale. The Jonker diamond was the first large diamond to be sold by the Central Selling Organization, and likewise it was the first of many purchases of unique large diamonds which Harry Winston Inc. was to make over the following years from the Central Selling Organization.

After Harry Winston purchased the diamond in 1935, a request was made by the De Beers Central Selling Organization, to leave the stone in London for some time, until the conclusion of the Silver Jubilee Celebrations of the Coronation of King George V and Queen Mary of the United Kingdom, enabling important dignitaries who were expected in London for the occasion, to inspect the diamond if they so wished. Mr. Winston kindly consented to this special request. Another reason has been adduced for this request. This was, that a suggestion had been made by several influential persons, that the Jonker Diamond would have made an excellent gift to King George V and  Queen Mary, to mark the 25th anniversary of their coronation. The purchase of the diamond was to be funded by voluntary popular subscriptions, but the laudable proposal never got off the ground. Unfortunately, the King died the following year, and was succeeded by his eldest son, the Prince of Wales, Prince Edward, who ascended the throne as Edward VIII. However King Edward VIII ruled only for a short period from Jan 20, 1936 to Dec 10, 1936. He abdicated in favor of his younger brother, Prince Albert, who became George VI, in order to marry the woman he loved, Mrs. Wallis Warfield Simpson, a divorcee.

The Jonker diamond eventually made it's trans-Atlantic trip to Mr. Harry Winston's office, in New York city. His immediate task was now to find an expert diamond cutter, in the United States, who was competent enough, to undertake the difficult task of cutting this large diamond. Finding such a person was not an easy task, as no diamond of comparable size or value, had ever been cut in the United States, before. The two larger diamonds, the Cullinan and the Excelsior, were both cut by J. J. Asscher & Co. of Amsterdam, Netherlands. But, Mr. Harry Winston was determined to cut the Jonker diamond  in the United States itself, and he chose Mr. Lazare Kaplan, who had descended from three generations of jewelers, to undertake the difficult task. Mr. Kaplan was an outstanding cleaver and cutter, who had learned the craft of diamond cutting in Antwerp, Belgium. He always insisted on the quality of a diamond, obtaining the maximum fire and brilliance, sometimes at the expense of quantity. Mr. Kaplan transferred his business activities to North America in 1914, and pioneered the establishment of the diamond cutting industry in Puerto Rico.

The clever diamond dealer Mr. Harry Winston, had previously assigned the cutting of the Pohl diamond, the constant companion of the Jonker diamond, to Mr. Lazare Kaplan, possibly as a test of his abilities, to undertake the more difficult task of cutting the larger Jonker Diamond. Kaplan came out with flying colors in this test, cutting the Pohl into 15 gems, all flawless except one, which nonetheless sold for $ 50,000. The largest diamond cut from the Pohl, was the 38.10 carat, emerald -cut diamond, that retained the name Pohl, and was once owned by Bernice Chrysler Garbisch, daughter of the founder of the Chrysler Motor Corporation, which now goes as Daimler-Chrysler Motor Co.

The cutting of the Jonker however posed a serious challenge to Lazare Kaplan, as this was the biggest diamond he had ever encountered, and more over it possessed a degree of frostiness on it's surface, rendering the cutting and polishing even more difficult. The company that insured the diamond, refused to cover the cutting of the diamond, even though they allowed the stone to be transported to New York, by ordinary registered mail  !

The Jonker was subjected to thorough examination and scrutiny both internally and externally, by Lazare Kaplan, a process that took several months. He also made several models of the diamond, to assist him in the studies. After an exhaustive study, Kaplan was convinced that there lay only one way in which the diamond could be cleaved. He marked the cleavage lines with Indian ink, but later realized that what resembled the cleavage plane, was not in fact a cleavage at all.

Eventually , on April 27th, 1936, he did cleave the diamond, splitting off a 35-carat section of the stone. This piece was later fashioned into the only marquise-cut gem from the diamond. He again performed two more cleavings, and the rest of the divisions were dons by sawing. Finally the rough Jonker diamond was cut into 13 pieces. The faceting and polishing of the pieces then began in earnest, and each of the 13 gems gave a final weight, that was very close to the estimated weight. The following table indicates the course of the cutting and polishing of the Jonker diamond.


Serial No of piece separated

Carat weight of piece Estimated ct. wt. of finished gem Actual ct. wt. of finished gem Cut

Final rank

1 35.82 17 15.77 marquise VIII
2 79.65 42 41.29 emerald II
3 43.30 20 19.76 emerald VII
4 54.19 30 25.78 emerald V
5 52.77 35 30.71 emerald IV
6 65.28 35 35.45 emerald III
7 13.57 6 5.70 emerald XI
8 53.95 25 24.91 emerald VI
9 10.98 5 5.30 emerald XII
10 220.00 150 142.90 emerald I
11 29.46 14 11.43 emerald X
12 27.85 14 13.55 emerald IX
13 8.28 4 3.53 baguette XIII


The largest diamond, which retained the name Jonker, originally weighed 142.90 carats. It was an emerald-cut with 66 facets. The stone was later re-cut to eliminate some flaws and improve it's brilliance. The re-cut stone also an emerald-cut, had 58 facets and weighed 125.35 carats. The Jonker I is one of the most perfectly cut diamonds in the world, and always attracted lot of attention when exhibited in different parts of the U.S.

The Jonker I was purchased by King Farouk of Egypt in 1949, but the whereabouts of the diamond became a mystery after he was deposed and exiled in 1952. The diamond however re-appeared again after some years, and the new owner of the diamond was Queen Ratna of Nepal.

The fate of the smaller products of the Jonker diamond are uncertain, probably because no records were kept of their movement, due to their insignificant sizes. But the Jonker II, which originally weighed 41.29 carats, but now had a modified weight of 40.26 carats, probably due to a slight re-cutting, came up for sale at a Sotheby's auction in Geneva in May 1994, and was sold for U.S. $1, 975, 000.

The Jonker IV, weighing 30.71 carats, and set in a platinum ring, came up for sale at an auction of  Sotheby Parke-Bernet Inc. in New York, and was sold to a private collector from South America for £ 277,000. During this sale the diamond was given an excellent G. I. A. rating, even though it was fashioned 30 years earlier, which was indeed a tribute to both the quality of the original rough stone and the skill of Lazare Kaplan. Again in Dec 1987, the Jonker IV came up for sale in New York, and was  purchased  for   U.S.  $ 1, 705,000.

The Maharajah of Indore was reported to be the purchaser of the Jonkers V, VII, XI and XII. The Jonker X was rumored to have been purchased by John D. Rockefeller Jr.


Last transaction and present owners of the diamond

The last transaction of the Jonker I diamond was in 1977, when the diamond was sold privately in Hong Kong for a sum of U. S. $ 2, 259, 000, to an anonymous buyer. It is believed that the same anonymous buyer still owns the diamond today.


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