Green diamonds – exceedingly rare, and, at least for now, cheaper than other coloured diamonds – are beginning to catch on with Asian collectors and investors. Since 2014, only 13 lots of green diamonds have made their way into Bonhams auctions – eight of which sold in Hong Kong. Diamonds in the “fancy colour” family are priced according to the vividness and purity of their colour. A pure green diamond can sell for upwards of US$1 million per carat at auction. Or even more. Chow Tai Fook Jewellery paid the most ever for a green diamond – US$16.8 million. That was the 5.03 carat, fancy vivid Aurora Green, which the Hong Kong jeweller bought at $3.3 million a carat at a Christie’s auction in May of 2016. The largest such diamond is the Dresden Green, a pear-shaped, 40.70 carat gemstone that is on display at the Albertinium Museum in Dresden, Germany. Fake Hong Kong diamonds cost me US$200,000 – and my fiancée “Green is one of the rarest diamonds,” said Paul Redmayne, head of jewellery sales at auctioneer Bonhams Hong Kong. “And if you look at it purely from an investment point of view, they’re very much undervalued.” The stones have been discovered in mines including in Brazil, Guyana, Venezuela, Zimbabwe and the Central African Republic. They were created by being bombarded by naturally occurring radiation, such as uranium. Authentication is especially important with these gems because swindlers can fabricate a “green diamond” by applying radiation to a common white diamond. They can also be hard to price because so few have sold on the open market compared to their other coloured cousins. “It’s one of the least understood diamonds,” said Redmayne. “Blues, reds and pinks get the coverage. But more collectors in Asia are now very at ease with the colour green.” Due to their mystery and rarity, they are not favoured with collectors and investors – at least not yet. That may mean an early acquirer could at some point in the future be handsomely rewarded, several diamond experts said. But, for now, they might work better for collectors than for short-term investors because it can be harder to find a buyer than for other diamonds, said Hazel Choi, a Hong Kong gemologist and collector. “In the long run, they will increase in value,” Choi said. “You’ll have to find the right buyer and that buyer will be someone who has a pretty comprehensive collection and has a lot of knowledge about gemstones.” A pure green diamond has a range of colour intensities, stretching from faint green to fancy deep green. They also can have a secondary hue, such as yellow, blue or brown. Pink, blue or green, these rare diamonds can fetch mega millions These variations can dramatically affect pricing, as does their comparative unfamiliarity with collectors and investors. In April, at the Sotheby’s spring auction in Hong Kong, a 1.97 carat fancy green diamond sold for US$596,279, the low end of its US$509,640 to US$700,755 estimate. “I think this could be a sign that investors haven’t really caught on to green diamonds yet,” said Choi, adding that some green diamonds being offered may be bargains as investors warm up to them. On October 3, Sotheby’s auctioned a “fancy vivid bluish” diamond weighing 1.38 carats for US$810,000, right between its estimated $710,000 to $920,000 price. Andrew Coxon, president of the De Beers Institute of Diamonds, said recent auction prices reflect positively on the growth of green diamond prices in recent years. They are currently “200 times more expensive than a colourless diamond of similar size and quality,” he said. Next month, Bonhams will auction off three lots of green diamonds, two of which it expects to hit the HK$1 million mark. The buzz around green diamonds comes as many wealthy Chinese have been adding diamonds to their asset portfolios. A report this year by diamond miner and trader De Beers Group found that 63 per cent of diamonds purchased in China are not meant for daily wear, suggesting collection. Chinese millennials are driving the market, which grew year-on-year by 3 per cent to US$66 billion last year, it said. For every 10,000 white diamonds, there is only one coloured diamond. Only about 3 per cent of diamonds submitted to the Gemological Institute of America are coloured diamonds. Pink has been a favourite. The pinks are nearly all from the Argyle Diamond Mine in a remote area of Western Australia. The mine is slated to close by 2020, which will likely boost the value of these gemstones, adding pressure on the attractiveness of green diamonds to collectors and investors. Hong Kong jeweller paid record price for rare pink diamond as part of 88th anniversary celebrations Pinks, too, have a history with Hong Kong. The largest, internally flawless, fancy vivid pink diamond is the CTF Pink, at 59.60 carats and previously known as the Pink Star, which sold to Chow Tai Fook Jewellery in April of last year at Sotheby’s in Hong Kong. It was the world’s most expensive gemstone auctioned, at $70.6 million. Mystery diamond buyer revealed: Hong Kong billionaire Joseph Lau spends US$48m on ‘Blue Moon Diamond’ for seven-year-old daughter Meanwhile, Hong Kong billionaire fugitive Joseph Lau paid US$48 million in November of 2015 for a fancy vivid blue diamond for his seven-year-old daughter Josephine. He named the 12.03 carat gemstone the “Blue Moon of Josephine.” He also bought a US$28.6 million, 16.08 carat pink diamond he named “Sweet Josephine,” and a US$9.5 million, 7.03 carat vivid blue gem that he called “Star of Josephine.” For now, there is a bit of a gamble on green diamonds. But for those who make a smart play, experts say, they may end up with a winning investment.