Current weight: 55.23 carats
Cut: Double rose cut (shield-shaped; unusual early cutting style)
Colour: Pale yellow
Origin: Golconda, India
First European documentation: Late 16th century; Nicolas de Harlay, Seigneur de Sancy, France
Current location: Louvre Museum, Paris, Apollo Gallery, since 1978
Sources: Louvre Museum documentation, louvre.fr; Balfour, I. (1987), Famous Diamonds, Christie's Publications
The double rose cut: a pre-brilliant gem
The Sancy's most distinctive physical characteristic is its unusual double rose cut, a form in which both the top and bottom of the stone are faceted in a dome configuration with no flat table and no flat base. This shape, rarely seen in modern diamonds which almost universally use some variant of the brilliant cut or step cut, was characteristic of early European diamond cutting before the development of the brilliant cut in the 17th century. The Sancy's double rose cut gives it a softer, more diffuse light return than a brilliant-cut stone, and its pale yellow colour and historic cutting style make it one of the most unusual major diamonds in any museum collection (Balfour, 1987, op. cit., pp. 130–131; Louvre documentation).
French and English royal ownership
Nicolas de Sancy sold the diamond to the English Crown in 1604, purchasing it to James I of England (James VI of Scotland). It remained in English royal possession until James's son Charles I pawned it to raise funds, eventually passing to Cardinal Mazarin, the chief minister of France who assembled one of the greatest gem collections in European history. Mazarin bequeathed his collection, including the Sancy, to the French Crown in 1661. Louis XIV incorporated the Sancy into the French Crown Jewels, where it remained through multiple French royal reigns (Balfour, 1987, op. cit., pp. 132–136; Louvre documentation).
Like the Regent, the Sancy was among the Crown Jewels stolen in the 1792 Garde-Meuble theft. Unlike the Regent, it was not immediately recovered. It reappeared in Spain in the possession of the Spanish royal family and was subsequently purchased by the Astor family of England. William Waldorf Astor purchased the Sancy in 1906 and it remained in the Astor family collection until it was sold to the Louvre in 1978 for approximately USD 1 million (Louvre Museum documentation; Balfour, 1987).
Primary sources
Louvre Museum documentation. louvre.fr. [Sancy Diamond: 55.23ct, double rose cut, pale yellow, Golconda origin. Current location Apollo Gallery. Acquired by Louvre 1978. Astor family ownership prior to sale.]
Balfour, I. (1987). Famous Diamonds. Christie's Publications, London, pp. 130–138. [Nicolas de Sancy acquisition in Turkey, Henri III and Henri IV lending, sale to James I (1604), Cardinal Mazarin bequest (1661), 1792 theft, subsequent disappearance, Spanish royal possession, Astor family ownership from 1906.]