Traditional heat treatment on rubies can be traced back to long ago in medieval Arabian and renaissance European texts, if not several centuries ago, said Daniel Nyfeler, managing director of Gübelin Gem Lab. This time-honoured treatment allows the chemical constituents in the stone to reorganise so as to make the gem more vivid and transparent permanently that Mother Nature did not provide. No other elements or substance will be added other than heating. Temperatures normally range from approximately 400℃to 1,800℃, and the duration from hours to months, as the intrinsic variations of rubies from different localities throughout the world require corresponding techniques of heating.
Given that there are other types of heat treatment applied to lower quality rubies including glass filling and diffusion treatment - the former enhances colour, clarity, weight and stability of the stone and the latter introduces additional chemical elements to improve the quality, heat treatment affects the value of rubies largely especially compared with unheated counterparts, leading to a huge price range of ruby in the market.
A common practice
Since the 1970s, Thailand has been the world’s most important centre of corundum heat treatment. Rubies from almost every locality around the world are imported and heat-treated in Thailand, mainly in Bangkok and Chanthaburi. “Heat-treated ruby is very common in the market as a whole. Literally, more than 95 percent of rubies sold in the trade are heat-treated,” noted Pornsawat Wathanakul, director of Gem and Jewelry Institute of Thailand (GIT). She believes that disclosed heat treatment of ruby is necessary, as “without heat treatment, there would not have enough good quality rubies to meet the demand”.
“Heat treatment of ruby is considered traditional, appropriate, and well-accepted,” Gary Roskin, executive director of International Colored Gemstone Associaton (ICA) told Hong Kong Jewellery. He said heat treatment improves the beauty of thousands of carats of rubies every year, and allows practitioners to create more ruby jewellery. “Otherwise, only the very wealthy would be wearing rubies, as there would not be enough available for everyone,” he added.
“Rubies that are opaque and have weaker colour or impurities can be enhanced by heat treatment. There is nothing wrong with this practice, provided that the treatment is fully disclosed to the client,” said Adrian Banks, product director of London-based Gemfields plc, leading miner and supplier of coloured gemstones, specialising in rubies from Northern Mozambique and emeralds and amethysts from Zambia. He said: “Our mines produce many different qualities of rubies. If our partners enhance these rubies, it allows more jewellery brands to use rubies, raising awareness of this precious gemstone and ultimately driving up the demand amongst consumers.”
Purchasing considerations
In the gemstone market, there is no lack of consumers who scramble for the most precious, unique and natural gemstones without any enhancement. That is why unheated ruby has been one of the hottest gemstones for fine jewellery and at auctions.
“Even though heated ruby does have value, consumers would prefer the best one in unheated category for the long-term investment,” revealed Phuket Khunaprapakorn, president of Chanthaburi Gem & Jewelry Traders Association, and Gemburi, manufacturer and wholesaler of ruby and sapphire in Thailand. Peeyush Bader from India-based V P Gems expressed that consumers would purchase unheated rubies by virtue of the human nature of possessing natural gemstones, even if the stone is in bad condition with inclusions or dark colour.
This preconception is more obvious amongst Chinese consumers who lack specific knowledge on ruby. Regarding this, chief researcher of National Gems & Jewelry Technology Administrative Center in China, Lu Taijin analysed that the misconception that only unheated rubies are the best has resulted in such purchasing behaviour, especially when considering the developing gemstone consumption market in China where many consumers regard jewellery purchases as an investment instead of an ornament.
Whilst, the family-run company Fai Dee Limited, dealing exclusively in Burmese rubies, bypassed this preference influence. Ravi Lunia, the fourth generation of the family, said that as long as the ruby’s origin is Burma where the rarest rubies come from, selling heated ruby is not an issue, as Burmese rubies always have value, rarity, history and reputation. Based on his observation, heated and unheated rubies are different markets, meeting with different consumers. Sometimes, “it is like personal satisfaction, to find which one satisfies you the most”.
Regarding this, according to Daniel Nyfeler, on one hand, ruby’s origin is about fame and pedigree, which has been developed into an actual brand. On the other, treatment is more related to the rarity and authenticity of the stone. “Both geographic origin and treatment are significant drivers of the value of ruby,” he added.
Pornsawat Wathanakul emphasised on ruby’s properties include the quality of 4Cs (colour, carat, cut, and clarity), treatment type, and origin (only for high quality rubies) for consumers to consider. Furthermore, Gary Roskin said, in most cases, buying ruby is all about consumer’s budget and personal choice. “The good news is that there is a ruby for every budget. Consumers just need to know the difference in value between quality and enhancement,” he said.
Education need
In fact, there is no comprehensive and globally-accepted quality grading system available for coloured gemstones, which makes buying rubies a difficult task requiring professional knowledge and the ability to avoid those who sell low-quality rubies at crazy prices by taking advantages of the reputation of Burmese rubies, the name of pigeon blood red, or the obsession consumers have for unheated stones.
On this issue, Gemfields plans to develop an educational programme, aiming to provide fundamental knowledge on ruby’s value, treatment and origin in 2016. In December 2015, the company will launch a new Bergdorf Goodman fine jewellery room in New York, the United States, collaborating with 18 designers from Bergdorf Goodman to create 50 pieces of jewellery by using a mix of heated and unheated rubies.
“For Gemfields, beauty is in the eye of the beholder. Coloured gemstones like rubies allow consumers to express their individuality, thus, our emphasis is on beauty, not whether it is unheated or heated,” explained Adrian Banks.
GIT also showed their concern over the public education on the nature of ruby. “The more understanding people have, the more confidence and less ambiguity in ruby purchasing,” said Pornsawat Wathanakul.
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