Lot 365. 'The Star of Sierra Leone Diamond Brooch', Harry Winston. Estimate 290,000 — 350,000 CHF. Photo: Sotheby's

Of floral motif, set with a pear-shaped diamond, surrounded with a similarly shaped stone weighing 3.25 carats, and five marquise-shaped diamonds weighing 2.86, 2.97, 3.74, 3.93 and 4.30 carats, further highlighted with marquise-shaped stones, unsigned, maker's mark for Jacques Timey.  

Accompanied by GIA report no. 5182202198, stating that the diamond weighing 3.25 carats is D Colour, Internally Flawless, Excellent Polish; no. 2185202200, stating that the diamond weighing 3.74 carats is D Colour, Internally Flawless, Excellent Polish; no. 2185202070, stating that the diamond weighing 4.30 carats is D Colour, VVS1 Clarity, Excellent Polish, together with a working diagram stating that the diamond may be internally flawless after minor repolishing. 

Note: "Harry Winston purchased the Star of Sierra Leone in 1972... Originally, the largest stone was a 143.20 carat emerald cut, of fine colour but flawed. Mr. Winston felt that such a large stone should be flawless... The top was sawed horizontally to remove the imperfections. The bottom piece was refashioned to a D-flawless emerald-cut of 35.52 carats. From the top piece that had been removed, six diamonds were fashioned; five of them were D-flawless. These six stones - weighing a total of 21 carats - were used in the Star of Sierra Leone brooch, arranged like the petals of a flower".

Excerpt from Laurence S. Krashes, The Ultimate Jeweler.

Sotheby's. Magnificent Jewels and Noble Jewels, Session 3, Geneva, 16 May 2017, 07:00 PM