David Bennett at the rostrum for the Magnificent Jewels and Noble Jewels sale in Geneva.

GENEVA - One hundred carats has become for me the magic number in diamonds. Over the last 25 years, I have sold seven diamonds weighing 100 or more carats in Geneva. The first, in November 1990, was the ‘Mouawad Splendour’ which reached CHF15,950,000 ($12,760,000), and established the world record price for a diamond at auction. Further record diamonds followed, such as the celebrated ‘Star of the Season’ in 1995.

The latest sale yielded two more: the ‘Graff Vivid Yellow’ diamond weighing 100.09 carats, which at CHF14,501,000 ($16,347,847) set two new world auction records for a yellow diamond and for a jewel by Graff; and a spectacular and rare diamond ring by Graff, featuring one of the largest brilliant cut diamonds in the world weighing 103.46 carats, which I hammered down at CHF4,309,000 ($4,857,794).

The sensational and rare fancy vivid yellow diamond ring, Graff, known as 'The Graff Vivid Yellow' sold for CHF 14,501,000.

While, of course, I am proud of these records, what I find so interesting about these sales is the history of the jewels and the people who create, wear and collect them.

A good example is the Van Cleef & Arpels necklace that was created for Jacqueline Auriol, the celebrated female French test-pilot, heralded as ‘the fastest woman in the world’.  At CHF245,000 ($276,203) the necklace sold for 12 times its presale estimate. This jewel embodies the perfect combination of fascinating provenance and unique design, from one of the greatest jewelers of the 20th century. It is truly a chef-d’oeuvre of post-war jewellery design.

Gold and diamond necklace, Van Cleef & Arpels, 1956 sold for CHF245,000.

I also adored the sumptuous belle époque diamond necklace from the collection of Flora Sassoon, and the accompanying photographs from the turn of the 20th century perfectly capture the essence of that era.

Flora Sassoon, circa 1900

I am already embarking on the quest for more fascinating jewels for our November sale in Geneva. The thrill of this job is not knowing which treasures will turn up next.

David Bennett is Chairman of Sotheby’s Switzerland and Chairman of the Jewellery Department for Europe and the Middle East.  Together with his colleague, Daniela Mascetti, Senior Specialist, International, they have written Understanding Jewellery (1989), and Celebrating Jewellery (2012).