A rare pink diamond could fetch up to $38 million at an upcoming Sotheby’s sale next month.

The May 17 sale of Magnificent Jewels and Noble Jewels in Geneva, Switzerland, will be led by the spectacular ‘Unique Pink’, a rare and exceptional Fancy Vivid Pink diamond weighing 15.38 carats. 

In addition to receiving the highest possible colour grading for a pink diamond from the Gemological Institute of America (GIA), the Unique Pink has been found to be Type IIa, displaying “exceedingly pure structure”. 

The stone’s exquisite pear shape and brilliant cut accentuate its exceptional saturation, placing it in a rarefied category even among the world’s most beautiful diamonds. The “Unique Pink” will be offered at auction with a pre-sale estimate of $28-38 million (CHF27-37 million).

David Bennett, Worldwide Chairman of Sotheby’s International Jewellery Division, comments: “It is difficult to imagine a diamond that better illustrates the term Vivid Pink than this outstanding stone. The colour is simply astonishing and, for its size, it is in my experience truly unique.”

The rough diamond which yielded the Unique Pink was cut and polished by Cora International, known worldwide for rare and unique diamonds of large sizes and vivid fancy colours. According to the GIA, “Although nature is largely to thank for the Unique Pink’s most striking and unusual attributes, the work of its cutter must not go unnoticed. The task of polishing the valuable rough crystal into the sparkling gem it is today required tremendous skill.”

The discovery of any gem-quality pink diamond is extremely rare. Of all diamonds submitted to the GIA each year, no more than 3 per cent are classified as coloured diamonds, and less than 5 per cent of those coloured diamonds are predominantly pink. Upon inspection by the institute, the hue, tone and saturation of the ‘Unique Pink’ was determined to be Fancy Vivid Pink – the strongest saturation possible and described as “absolutely mesmerizing”.

A GIA monograph on the Unique Pink states that it is “exceptionally rare for any natural diamond to reveal Fancy Vivid Pink color, but for one of 15.38 carats to exhibit such tone and saturation is astonishing”.

Sotheby’s currently holds auction records for blue, pink, yellow, green and colourless Diamonds. These include:

• The 12.03-carat Blue Moon of Josephine, which set a world auction record and record price-per-carat for any diamond or gemstone when it sold for $48.46 million in November 2015.

• The 24.78-carat Graff Pink, which set a world auction record for any pink diamond selling for $46.15 million in November 2010.

• A 118.28-carat diamond which fetched $30.60 million in October 2013, serting a world auction record for any colourless diamond.

• The Graff Vivid Yellow, which sold for $16.34 million in May 2014, a world auction record for any yellow diamond.

• A green diamond weighing 2.52 carats which sold for $3.07 million in November 2009 setting a world auction record price-per-carat for any green diamond.