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Rare Diamonds Go Up For Auction

A stunning selection of gems are due to go on the selling block at Phillips Hong Kong Fall Jewel and Jadeite auction.

If you happen to be at the Mandarin Oriental, Hong Kong on November 27, you’ll be pleased to know you’ll be sharing floorspace with an impressive number of incredibly rare gemstones, as auction house Phillips prepares to begin its fall sale of Jewels and Jadeite.

We spoke to the Head of Jewellery of Phillips Asia, Terry Chu, who was happy to share her unique insights on the top lots that are about to go up for sale, and who’s likely to be snapping them up.

Tell us about the fancy intense green diamond that’s headlining the fall auction. 

I am thrilled to be leading our sale with a green diamond this season; the extremely rare fancy intense diamond is a feat of nature and a stone of this quality is an exceptional find. The occurrence of a natural green diamond is so rare that historically very few examples were documented. This explains why this unusual green gem, unlike its fancy coloured counterparts, remains less known to the majority of the general public. Nevertheless, green diamonds are one of nature’s most miraculous creations. In the past few decades, only a number of the purest green diamonds appeared in international auction market, so we are extremely happy to be offering this ‘fancy intense green diamond’ in our auction.

The green colour of a diamond can only develop under very distinct conditions, namely exposure to alpha-particle radiation for millions of years. The radiation causes a defect in the lattice structure of the diamond which subsequently alters its optical characteristics. However, the majority of ‘green’ diamonds only possess a superficial green outer coating. Once cut and polished, such diamonds will lose their green colour and appear to be colourless or yellowish. Only in extremely rare cases will the intensity of radioactivity could penetrate through the entire diamond rough, causing a homogenous green ‘body colour’.

Phillips auction

The purity of a stone’s green body colour is the next important factor determining its value. Blue and yellow are the most commonly found secondary colours of a green diamond. Pure green colour is exceedingly unusual, fancy green colour more so. A rich, uniform and saturated green body colour is not the only striking characteristic of this important coloured diamond, a remarkable size is another attribute deeming it highly exceptional. While most green diamonds, including those displaying secondary colours, very rarely exceeds 2 carats, this cushion-shaped fancy intense green diamond weighs close to 6 carats.

Have you seen an increased trend for coloured diamonds at auction?

Historically, fancy intense and fancy vivid stones have fetched the highest prices at auction and, when they appear, such offerings cause a great deal of excitement in the collecting community.

In addition to our star lot, we will also be offering “The Golden Drop”, an internally flawless fancy vivid yellow diamond and diamond ring of 8.09 carats (estimate: HK$5,500,000 – $6,300,000). This attractive yellow colour is what the trade would describe as ‘Zimmi’, a relatively modern term for yellow diamonds with an exceptional saturation of hue. Zimmi is a mining area located in Sierra Leone of Africa, known to produce the world’s best yellow diamonds.  Scientist classify diamonds into two main “types”, type I and type II, based on the atomic structure of the stone. Recent research studies shown that many of the ‘Zimmi’ diamonds fall into the Type Ib category, making up only 0.1% of natural diamonds.

What are your other top picks from the lots on offer?

The evergreen theme that ties many of the highlight lots together this season will, of course, include examples of fine jadeite. Jadeites have traditionally been a cornerstone of the Asian jewellery market, and continue to form an important part of our curated offerings. Amongst the highlights are a very fine jadeite bangle (estimate: $13,500,000 – $17,000,000); its classical circular form symbolises fullness and perfection. The evergreen collection also includes a no-oil Colombian emerald and diamond ring of 19.90 carats (estimate: $9,000,000 – $12,000,000). Emeralds are regarded as an emblem of eternal love in Greek mythology, and green is worn to honour the goddess of love, Aphrodite. Wearing an emerald was also believed to reveal the truth or falseness of a lover’s oath.

Phillips auction

Do you find auctions pieces are purchased for personal wear or for posterity?

Each collection is built upon different motivations and visions; buyers collect jewellery for personal adornment, as an alternate investment strategy, appreciation of heritage, aesthetics and design, or to build a collection of heirlooms for the next generation. There are renowned collectors in the region who have amassed rare stone collections for their children. There are also pieces that specifically speak to this, for example the impressive pair of jadeite ‘double-gourd’ and diamond earrings (estimate: HKD 4,500,000 – 5,500,000) in our sale. The design is highly versatile and can be unattached to form two pendants. I could see a collector wearing these and then passing them down to her children as family heirlooms.

One of the barriers of entry for antique and period jewellery in Asia was a resistance towards previously-owned jewellery, however we are seeing a change in attitudes towards collecting. The younger generation of collectors appreciate – aside from the intrinsic value of gemstones – the history, heritage and craftsmanship behind these pieces. They are collecting for personal wear and for posterity. When wearing antique of period pieces, taste-makers can also be assured that they are wearing unique finds, and this appeals to many collectors.

What is your personal favourite when it comes to diamonds?

My personal favourite is an emerald-cut fancy intense pink diamond and diamond ring of 0.95 carat (estimate: HKD1,300,000 – 1,600,000).

Pink diamonds are considered among the rarest hues of diamonds, where the best pink diamonds are known to be mined at Argyle in the remote north of Western Australia, also the world’s largest producer of natural coloured diamonds. Moreover, only 5% of diamonds mined from Argyle are of gem quality, and less than 1% of those are pink. Every one million carats of rough diamonds mined typically yields only one carat of gem-quality pink diamonds. Even rarer are the highly saturated pink diamonds which are graded as ‘intense’ or ‘vivid’ and those that are over 0.5 carat are truly scarce. With the expectancy of the Argyle mine’s supply of diamonds anticipated to continue only until 2020, good quality, fancy pink diamonds are expected to remain highly sought after and increasingly difficult to find.