An unheated Kashmir sapphire and diamond ring leads Bonhams upcoming rare jewels and jadeite sale in Hong Kong on May 27.

The 12.92 carat Kashmir sapphire was recently discovered in a client’s bank vault and the gemstone is estimated to fetch between HK$950,000 and HK$4,000,000 ($120,000 – $510,000), Bonhams said.

Bonhams Asia Director of Jewellery Graeme Thompson assessed the sapphire and believed it to be of Kashmir origin. The gemstone was then sent by Bonhams to Switzerland for scientific testing where it was confirmed as an extremely rare Kashmir sapphire, which had previously been assessed by other auction houses at HK$30,000-50,000 ($3,800-$6,300).

“Kashmir sapphires are the rarest of gemstones and collectors are prepared to pay princely sums for top-quality specimens, which have experienced a 970 per cent price increase for sapphires over the past decade,” commented Thompson. “We are delighted to headline this extremely rare piece in our upcoming sale. Sapphires were first discovered in Kashmir around 1880 but most Kashmir mines rapidly depleted soon after. Termed as 'blue velvet' due to the superiority of their superb cornflower blue hue, most Kashmir sapphires that appear on the market today were discovered more than 100 years ago.”

Alongside this piece, the Hong Kong sale features an exceptional range of rubies, emeralds, spinels, diamonds and a collection of signed jewellery from the most famous houses including Van Cleef and Arpels, Cartier, Harry Winston, Graff, Chopard and Bulgari across some 168 lots valued from HK$20,000 to HK$5,000,000.

Emeralds and Rubies: Bonhams presents best in class Burmese 'Pigeon's Blood' ruby and diamond ring (estimated at HK$3,500,000-5,000,000) and an 8.88 carat Colombia ‘No Oil’ emerald and diamond ring (estimated at HK$5,000,000-6,000,000) from a private Asian collector who purchased the pieces in a Hong Kong auction in May 2016 and is now looking to sell both rings to capitalise on price increases since, and to reinvest in higher value items.

“The market has experienced the biggest price increases for emeralds and rubies which respectively have seen a 1,900 per cent price increase for emeralds and a 1,100 per cent increase for rubies in the past 10 years”, said Thompson.

Spinels: According to Bonhams, there has been a noticeable interest in spinel with many collectors recognising their value and wanting to buy the best examples, with pieces over 10 carats considered incredibly rare. The international auction house still maintains the world record for the sale of exceptional 19th century large octagonal step-cut 50.13 carats spinel and diamond jewel for £962,500 in April 2015.

For its upcoming sale in Hong Kong, Bonhams features a 36.68 carats pear-shaped spinel and diamond necklace, estimated at HK$3,000,000-HK$5,000,000.


DIAMOND INSIGHT

Bonhams offers some insights into how best to appreciate the different varieties of fancy coloured diamonds, which Thompson explains “have seen the greatest price gains in the past 10 years with fancy blue and fancy pink diamond prices rising the most due to the rapid reduction in supply. The value of yellow diamonds are increasingly on the rise while red and green diamonds are the rarest to be found.”

Yellow Diamonds: After a dip in demand yellow diamonds, especially vivid yellows, are picking up again in popularity with many jewellery houses such as Tiffany’s and Graff using them in their new collections.

Pink Diamonds: The Argyle Diamond Mine in Western Australia produces between 90 per cent and 95 per cent of the world’s pink diamonds. However, as the mine’s diamond seams are depleting fast with its estimated closure by 2021, large gem-quality pink diamonds from the mine are already in low supply and as such this means pink diamonds are becoming increasingly rare. Consequently, over the past 10 years, the price of pink diamonds has increased by 443 per cent (source: Leibish & Co).

Green Diamonds: Fancy green diamonds are among the rarest of all fancy coloured diamonds. The cause of colour in green diamonds is natural radiation from deep within the earth’s surface. Green is the colour between blue and yellow, so diamonds of bluish green or yellowish green hue are a natural progression of colour that has become very collectible in recent years.

Blue Diamonds: Blue diamonds are the most sought-after natural colour diamonds and the supply and demand ratio makes them amongst the most expensive to purchase. According to The Robb Report, just 10 years ago, a buyer could have bought a vivid blue diamond for $200,000 to $300,000 per carat; today that same stone is fetching $2 million to $3 million per carat. This tenfold increase in value surpasses the growth rate of the FTSE 100 and the S&P 500 Index and also the housing market /real estate market.

There is only one source that continues consistently to produce the finest blue diamonds - the Cullinan Mine in South Africa - and its production has dwindled to a few dozen stones a year. A one carat vivid blue diamond can command roughly ten times more than a light-blue stone of the same size, according to the Fancy Color Research Foundation, whose recent figures show that between 2006 and 2014, blue, pink, and yellow diamonds experienced an average appreciation of 154.7 per cent.

Red diamonds: Red diamonds are the rarest of all, and the largest in the world among them, The Moussaieff Red, is 5.11 carats, which was discovered in Brazil but these days most reds are coming from the Argyle Mine, albeit nothing nearly that size. Anything over one carat is considered large and incredibly rare today.