Rough weight: 3,106.75 carats (approximately 621 grams)
Found: 26 January 1905, Premier Mine, Cullinan, Transvaal (now South Africa)
Finder: Frederick Wells, surface manager, Premier Mine
Colour: D (colourless), Type IIa
Cut into: 9 major stones (Cullinan I–IX) and approximately 96 smaller brilliants and polished fragments
Largest stone: Cullinan I (Great Star of Africa), 530.20 carats, pear brilliant
Current location: Crown Jewels, Jewel House, Tower of London
Sources: Tower of London official records, hrp.org.uk; Balfour, I. (1987), Famous Diamonds, Christie's Publications
Discovery and acquisition by the Transvaal government
The Cullinan was found at the Premier Mine, a mine that had been notable for producing exceptionally large and high-quality diamonds since its opening in 1902. The Transvaal government purchased the stone for £150,000 in 1907 and presented it to King Edward VII of Britain on his 66th birthday as a gesture of goodwill following the end of the Boer War. The presentation was intended to symbolise the reconciliation between the Boer Transvaal and the British Empire (Balfour, 1987, op. cit., pp. 68–74; Tower of London documentation, hrp.org.uk).
The cutting: Asscher brothers of Amsterdam
The task of cutting the world's largest gem diamond was assigned to the firm of I.J. Asscher & Co. of Amsterdam, at the time one of the world's most respected diamond cutting operations, known for developing the Asscher step cut. Joseph Asscher studied the stone for several months before deciding how to cleave it. On 10 February 1908, Asscher placed a steel blade in a prepared groove in the stone and struck it with a mallet. On the first blow, the blade broke. On the second blow, the Cullinan cleaved exactly as planned (Balfour, 1987, op. cit., pp. 74–78; documented in multiple accounts of the Cullinan cutting).
The cleaving of the Cullinan was one of the most technically demanding operations in the history of gem cutting. Asscher and his team of three cutters worked for eight months to produce the nine major stones and smaller polished goods. The cutting took place in Amsterdam under close security; detailed records were kept of every stone produced (Tower of London documentation; Balfour, 1987).
The nine major stones: weight and current location
| Stone | Weight (carats) | Cut | Current location |
|---|---|---|---|
| Cullinan I (Great Star of Africa) | 530.20 | Pear brilliant | Sovereign's Sceptre with Cross, Tower of London |
| Cullinan II (Second Star of Africa) | 317.40 | Cushion brilliant | Imperial State Crown, Tower of London |
| Cullinan III | 94.40 | Pear brilliant | Private (Crown personal collection) |
| Cullinan IV | 63.60 | Square cushion | Private (Crown personal collection) |
| Cullinan V | 18.80 | Heart brilliant | Private (Crown personal collection) |
| Cullinan VI | 11.50 | Marquise brilliant | Private (Crown personal collection) |
| Cullinan VII | 8.80 | Marquise brilliant | Private (Crown personal collection) |
| Cullinan VIII | 6.80 | Oblong brilliant | Private (Crown personal collection) |
| Cullinan IX | 4.39 | Pear brilliant | Private (Crown personal collection) |
Source: Tower of London official records, Historic Royal Palaces, hrp.org.uk; Balfour, I. (1987), Famous Diamonds, Christie's Publications, London.
Cullinan I: the Great Star of Africa
At 530.20 carats, the Great Star of Africa remained the world's largest cut diamond for most of the 20th century (it was surpassed in 1985 by the Golden Jubilee, 545.67ct, from the same Premier Mine). It is set at the head of the Sovereign's Sceptre with Cross, the principal sceptre used at coronations, which is displayed in the Jewel House at the Tower of London when not in ceremonial use. Cullinan I can be detached from the sceptre and worn as a pendant or brooch, and has been worn by multiple British monarchs (Tower of London official records, hrp.org.uk).
Primary sources
Tower of London official records. Historic Royal Palaces, hrp.org.uk. [Cullinan I in Sovereign's Sceptre (530.20ct pear brilliant); Cullinan II in Imperial State Crown (317.40ct); discovery date 26 January 1905; weight 3,106.75ct; cutting by Asscher Bros. Amsterdam.]
Balfour, I. (1987). Famous Diamonds. Christie's Publications, London, pp. 68–85. [Complete history: discovery by Frederick Wells, Transvaal government purchase (£150,000), presentation to Edward VII (1907), Asscher cutting methodology, cutting timeline (8 months), nine major stones with weights and cuts.]