This glorious colorless, cushion-shaped diamond with a weight of 245.35 carats ranks as the sixth largest diamond in the world. The original rough stone, an irregular octahedron without definite faces or shape weighed 650.80 (metric) carats; it was found in the Jagersfontein Mine towards the end of 1895. A consortium of London diamond merchants comprising the firms of Wernher, Beit & Co., Barnato Bros. and Mosenthal Sons & Co. acquired the Jubilee together with the Excelsior. At first the stone was named the Reitz in honor of Francis William Reitz, then president of the Orange Free State in which Jagersfontein is located.
In 1896 the consortium sent the diamond to Amsterdam where it was polished by M.B. Barends, under the supervision of Messieurs Metz. First, a piece weighing 40 carats or so was cleaved; this yielded a fine clean pear shape of 13.34 carats which was bought by Dom Carlos I of Portugal as a present for his wife. The present whereabouts of this gem are unknown. The remaining large piece was then polished into the Jubilee. When during the cutting it became evident that a superb diamond of exceptional purity and size was being produced, it was planned to present it to Queen Victoria. In the end this did not happen and the diamond remained with its owners. The following year marked the Diamond Jubilee of Queen Victoria (the 60th anniversary of her coronation) so the gem was renamed the Jubilee to commemorate the occasion. In the world of diamonds the event was also marked by the introduction of of the Jubilee cut; this has the characteristics of both the brilliant and rose cuts in that the table is replaced by eight facets, meeting in the center, the total number of facets being increased to 88. This cut was short-lived and is not often encountered today.
In 1900 the consortium displayed the Jubilee at the Paris Exhibition where it was one of the centers of attention. At the time it was valued at 7,000,000 francs. Shortly afterwards Sir Dorabji Jamsetji Tata bought the diamond. He was the Indian philanthropist and industrialist who laid the foundation of his country's steel and iron industry; these and cotton mills created by his father formed the cornerstone of modern India's economic development.
Sir Dorabji Jamsetji Tata died in 1932. In 1935 his heirs sent the Jubilee for sale at Cartier, who in December of that year mounted it in a display of historic diamonds. For a buyer the firm first looked to the Gaekwar of Baroda who in 1928 had appointed Cartier as his sole advisors on purchases of precious stones. Their representatives were prepared to sell the Jubilee for the price of £75,000. Having sought authorization from the treasury department in Baroda for the purchase, and despite encouragement from its officials, the Gaekwar opted not to buy the diamond. So in 1937 Cartier sold the Jubilee instead to M. Paul-Louis Weiller, the Paris industrialist and patron of the arts. The diamond's former setting was changed into a brooch with a number of diamond baguettes, resembling either a six-pointed star or a stylized turtle.
Mr. Weiller was always generous about loaning the Jubilee to exhibitions including one staged at the Smithsonian Institute in Washington in 1960 and another held in Geneva in December of the same year. In 1966 the Jubilee returned to South Africa where it was featured in the De Beers Diamond Pavilion in Johannesburg.
Mr. Robert Mouawad has since bought the Jubilee which is now the largest gem in his great collection. It has been graded as E-color, one grade away from completely colorless, and VVS2 clarity. He is quoted as saying: "If we refer to the human contribution brought to a diamond, my favorite would be the Jubilee for its outstanding cut for the period." Source: Famous Diamonds by Ian Balfour, and the Mouawad website, which is where I found the stone's color and clarity grade.