Joseph Asscher (1871-1934) was a Dutch master diamond cleaver and a member of the Asscher family of Amsterdam, one of the great houses of the European diamond trade. He is best remembered as the cutter who, on 10 February 1908, struck the first cleavage on the 3,106-carat Cullinan rough at the Asscher works in Amsterdam, the largest gem-quality diamond ever recovered.

Family and firm

The Asscher family had been in the Amsterdam diamond trade since 1854, when Joseph's grandfather Joseph Isaac Asscher established a small cutting works. Joseph's father Isaac Joseph Asscher and his uncle Abraham Asscher developed the business into the Asscher Diamond Company, which by the late nineteenth century was one of the leading firms in the city. Joseph and his brother Abraham eventually took the business through its most celebrated period and its near-destruction in the Second World War.

The Cullinan

The Cullinan rough was discovered at the Premier mine in the Transvaal in 1905. After being purchased by the Transvaal government and presented to King Edward VII, the rough was sent to the Asschers in 1907 for cutting. The contract specified that the firm would receive only the cleavage offcuts as payment for the work. Joseph Asscher studied the rough for several months, scribed the cleavage line and prepared a special steel cleaving knife. On the first attempt the knife snapped without splitting the stone. He prepared a second knife and, on 10 February 1908, struck successfully. The popular story that he fainted after the cut is colourful but probably apocryphal. The cutting yielded the Great Star of Africa, the Lesser Star of Africa and seven other major stones, all of which entered the British Crown Jewels or the personal collection of the Royal Family.

The Asscher cut

The square step cut now known as the Asscher cut was developed by Joseph Asscher and his brother Abraham in 1902, six years before the Cullinan work. It is a square modification of the emerald cut, with cropped corners producing an effective octagonal outline, deep step facets and a high crown. The cut was patented and remained an Asscher signature for several decades. A modernised Royal Asscher cut, with seventy-four facets rather than the original fifty-eight, was introduced by his descendants in 1999 to mark the firm's 145th anniversary.

War and aftermath

Joseph Asscher died in 1934, before the German occupation of the Netherlands. During the Second World War the Asscher family, like much of the Amsterdam diamond trade, was decimated. The Asscher works were stripped, and many family members and workers were murdered in the camps. The firm was rebuilt after the war by Joseph Asscher Jr. and Louis Asscher and remains active under the Royal Asscher name today, the royal designation having been granted by Queen Beatrix in 1980.

Significance

Joseph Asscher's place in the history of the trade rests on two achievements. The cleaving of the Cullinan demonstrated the highest level of technical and nervous control in the cleaver's craft. The development of the Asscher cut introduced a step-cut style that has remained continuously in use for more than a century. Together these accomplishments make him one of the most consequential figures in modern diamond cutting.