The Allnatt Diamond at Sotheby’s Geneva

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Today is auction day at Sotheby’s Geneva – the ‘Magnificent Jewels and Noble Jewels’ auction is about to start.

Here is a fantastic video from Sotheby’s with the sale highlights:

To browse the sale’s catalogue, click here.

One of the major highlights of the sale is the fabulous Allnat Diamond – Historical and Highly Significant Fancy Vivid Yellow diamond and diamond brooch, circa 1952:

Notes from Sotheby’s Catalogue

The Allnatt Diamond

The Allnatt diamond is one of the world’s most significant and historical Fancy Vivid Yellow diamonds, celebrated for its richly saturated golden colour, enchanting older cutting style and elegant 1950s mounting by Cartier.

South African Diamond Deposits

The discovery of the 10.73-carat Eureka yellow diamond in 1867 kickstarted the South African diamond rush. In the ensuing decades, scores of immigrants tried their luck in the Cape Colony, effectively creating the modern diamond mining industry. Because the South African deposits are rich in nitrogen, they have yielded most of the world’s most important yellow diamonds, including the 545.65-carat Golden Jubilee, the 205.07-carat Red Cross and the 128.54-carat Tiffany Yellow Diamond. In generations past, the term ‘Cape diamond’ designated light yellow tinted diamonds towards the tail-end of the D to Z range in reference to the vast quantity of yellow diamonds found in South Africa.

The Allnatt diamond was most likely produced by the South African De Beers Millennium Mine. Though its exact date of discovery is unrecorded, the diamond’s older cutting style suggests it was fashioned in the late 19th or early 20th century. As such, the manufacture likely predated the use of sawing, so the Allnatt’s shape must mirror the outline of the original rough.

Major Alfred Ernest Allnatt

The diamond is named after its first documented owner, Major Alfred Ernest Allnatt, a renowned British sportsman, racehorse owner, philanthropist, collector, and arts patron.

In 1959, Major Allnatt famously acquired ‘The Adoration of the Magi’ (1634) by Peter Paul Rubens at Sotheby’s for the then record-breaking sum of 250,000 GBP. The altarpiece had been created for the convent of the White Nuns in Louvain, modern-day Belgium. There, it hung until the dissolution of the monasteries during the French Revolutionary period and was subsequently acquired by the second Earl Grosvenor in the late 18th century. The painting remained with his descendants until the second Duke of Westminster decided to part with it in 1959. Major Allnatt bequeathed the Rubens altarpiece to King’s College Chapel Cambridge, where it remains today.

During his lifetime, Major Allnatt loaned several important old master paintings to the National Gallery in London, including canvases by Salomon van Ruysdael, Paolo Veneziano, Giorgione, Frans Hals and George Stubbs. After his passing, the National Gallery received ‘Salomon Receives the head of John The Baptist’ by Caravaggio, two Nicolas Poussin landscapes and an Edouard Vuillard from his estate.

Mounting by Cartier

In the early 1950s, Major Alfred Ernest Allnatt purchased the yellow diamond, still weighing 102.07 carats. He proceeded to have it mounted as a brooch by Cartier. Cartier’s original design drawing is dated 1952, whereas the invoice for the completed brooch is dated 24 September 1953. The Allnatt forms the heart of a flowerhead composed of openwork, brilliant-cut diamond-set petals enhanced with baguette diamonds.

The design is highly reminiscent of Cartier’s mounting created in 1952-1953 for another legendary coloured diamond, commissioned by an even more prestigious British client: Queen Elizabeth II’s Williamson Pink Diamond. The future Queen received this diamond as a wedding present in 1947 and subsequently had it mounted by Cartier as a brooch, which she wore throughout her long and prosperous reign.

Sale and Repolish

The Allnatt Diamond was last offered at auction in Geneva in May 1996, achieving the outstanding result of 3,043,496 USD. Its property designation read ‘Property of a Lady’. At the time, the diamond weighed 102.07 carats and was graded Fancy Intense Yellow by the GIA. Subsequently, the stone was carefully repolished to its current 101.29 carats. This minimal loss in weight, while having a negligible impact on the diamond’s outline and cutting style, brought the colour up to Fancy Vivid Yellow Colour.

The Allnatt was certified by the Gemmological Institute of America in 2000 and again in 2010, each time receiving a special letter. The GIA found no internal graining, colour zoning, or fluorescence in the stone. Like the majority of South African yellow diamonds, it was revealed to be type Ia. The GIA introduced its trademarked Monograph in 2009, a special distinction awarded to only the most remarkable diamonds. In 2010, the Allnatt became one of the first diamonds to receive this honour.     

The Splendor of Diamonds

The Smithsonian Museum of National History in Washington DC exhibited the Allnatt Diamond in the summer of 2003 as part of the highly prestigious exhibition ‘The Splendor of Diamonds’, which reunited seven celebrated diamonds, each representing the best specimen of their respective colours. The Allnatt was joined by the 203.04-carat D Colour De Beers Millenium Star, the 5.11-carat Fancy Red Moussaieff Red, the 5.54-carat Fancy Vivid Orange Pumpkin Diamond, the 59.60-carat Fancy Vivid Pink Steinmetz Pink, the 27.64-carat Fancy Vivid Blue Heart of Eternity and the 5.51-carat Fancy Deep Blue-Green Ocean Dream.  

Credits: Sotheby’s website