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Jewellery’s Naughty Little Secret: Treated Gemstones

Unbeknownst to most jewellery consumers, gemstones are often treated, filled with glass and even irradiated, yet retailers rarely disclose this.
Coloured gemstones | Source: Shutterstock
By
  • Sarah Shannon

LONDON, United Kingdom — "Here in the US, if it's pretty, it sells," says Gary Roskin, executive director of the International Colored Gemstone Association. Processes like heating gemstones to enhance their colour are so common that "no-one is really concerned," he adds, but other treatments like filling fractures with lead glass to hide the poor quality of stones are also commonplace and "need to be disclosed all the way to the consumers."

According to the Gemological Institute of America which examines more than two million diamonds, coloured stones and pearls each year for grading and analysis, these treatments range from bleaching to surface coating to dyeing to irradiation (where gems are exposed to an artificial source of radiation to change their colour). Laser drilling is also used to remove dark spots on stones, while lattice diffusion, where an element such as beryllium is penetrated into rubies and sapphires to enhance the colour is common.

And yet disclosure isn’t always the norm. In a competitive market worth $310 billion according to Euromonitor, the potential negative sales impact of disclosing treatments is often seen as a commercial liability. It’s a stance that may surprise consumers increasingly interested in transparency and ethics.

The Gemological Association of Great Britain estimates that 98 percent of rubies are treated; heated, glass-filled or otherwise subjected to diffusion and flux techniques. Blue topaz is almost entirely treated, sapphires are 95 percent treated in some way by either glass filling, diffusion or heat treatment, while citrines are often heat-treated, according to gemology and diamond tutor Julia Griffith. Aquamarines are heat-treated, emeralds are often filled with oil or resins to hide fractures and turquoise is resin-coated. (Enhanced coloured diamonds are “not common,” however, Griffith says, and any treatment of diamonds is usually clearly described at point of sale).

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“I would be surprised how many [stones] are treated” if I hadn’t studied it, says Griffith. “It’s accepted in the trade that all rubies are treated but it’s not told to the consumer,” she continues. While many gems require treatment to produce the colours consumers have come to expect, “people should be able to ask questions from their jeweller” and get honest answers, she adds.

The treatment of gemstones has been going on for centuries but the increasingly technologically-savvy treatments — and the difficulty in detecting these — makes things ever more complicated and often retailers hide behind these technicalities to avoid disclosing treatments to consumers, Griffith says. That or they simply don’t know. “It’s not always made very obvious to the customer because it could be quite a turn off. It’s a resistance to disclose or not knowing themselves and part of that is because it can be so complicated and yet so common.”

It's accepted in the trade that all rubies are treated but it's not told to the consumer.

To be sure, the supply chain for gemstones can be long and complex: miners often sell to “rough holders” who then sell to manufacturers who cut and polish. Gems are then sold onto wholesalers before they reach retail jewellers. Treatments can occur at any point in the process, making disclosure to the end consumer even harder, industry sources say.

Rubies that are not treated “are rare, and depending on the four C’s (same as diamonds), can reach record-breaking prices,” according to Gabriella Harvey, director of procurement and product services at Gemfields, one of the world’s largest coloured gemstone miners, which specialises in ethical sourcing. Heating, which improves colour, clarity and durability, allows for a broader customer base to enjoy coloured gemstone jewellery, she adds.

“Treatments are widely accepted, not only with rubies but with all other gemstones. The crucial thing is disclosure,” says Harvey. “We lead the industry with our approach to transparency and treatments is an area where this is crucial for consumer confidence.”

While suppliers and cutters may be increasingly transparent about it, jewellery retailers, particularly fashion jewellers, are lagging behind. “For many years, retail jewellers didn’t think about it. The miners would send to suppliers, suppliers would enhance them and because the retailer didn’t have the education to question what was coming from the suppliers, or the supplier felt it was traditional that these gems would need an enhancement of some kind,” the practice continued, according to Roskin from the International Colored Gemstone Association (ICA). “It never had an importance that it has today,” he adds. Today the ICA — with 750 members; mostly miners, cutters and gemstone suppliers — has a code of practice which includes mandatory disclosure of treatments.

“We are trying to teach the retailers what’s out there and what’s available and how to detect it and when it’s not detected what labs can be used,” Roskin says. “We tell the retailers they should be much more actively searching out the supplier that is going to tell them what’s happened to the stone that comes from out of the ground.”

Mandatory disclosure of the treatment of diamonds is required for certified members of the UK-based Responsible Jewellery Council. Coloured stones are soon to be included in the product disclosure, according to Anne Marie Fleury, director of standards and impacts. The body has just over 1,000 members, including luxury jewellers Van Cleef & Arpels, Cartier, Chopard, Boucheron and Bulgari. But that’s a drop in the ocean of the total industry and many lower-priced fashion jewellers are nowhere to be seen.

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Mostly you pay for what you get, but businesses need to tell people what they are buying.

The World Jewellery Confederation, or CIBJO, publishes Blue Book guides with globally accepted standards for the industry including requirements to disclose treatments of gemstones at point of sale and in written material. But it’s a voluntary code and not enforced.

In the US, Federal Trade Commission rules state it is unfair or deceptive to fail to disclose that a gemstone has been treated if the treatment is not permanent, the treatment creates special care requirements for the stone or the treatment has a significant effect on the stone’s value.

On the lower-ground floor of high-end department store Selfridges in central London, the Astley Clarke concession offers a blue diamond wrist piece for £9,950 (about $13,000) sat below a glass counter on a taupe suede box. The “Firework” cuff has several thousand small blue stones set in yellow gold. The brand’s website lists the gem as “blue diamonds,” but as a sales assistant brightly admits, the gems are treated. She also points out the £695 mini coloured diamond halo hoop earrings with yellow, red, white, green, black and blue diamonds that are also treated and a popular choice amongst shoppers.

“Our blue diamonds are irradiated, this is a safe and stable treatment, we do not treat them ourselves but we only buy certified stones that are tested to ensure they follow the strict regulations,” says Emilie Robichaud, senior product development manager at Astley Clarke. “Our sapphires are heat-treated and some of our agates are dyed. These are widely used and accepted methods of treatment. All our sales staff are trained and do explain to customers who enquire. Our experience on the whole is that for pavé and beads, customers are not overly concerned. We strive to be open and honest about the gemstones we use and any treatments that have been applied to them.”

Kiki McDonough, the British jeweller known for her coloured gemstones, has a “Candy” collection which includes a “green amethyst” and diamond drop earrings for £2,300 (about $3,000). Green amethyst is formed by heating or irradiating amethyst or yellow quartz. A spokesperson declined to comment.

At London’s Selfridges department store on a busy afternoon, shopper Bell Hendricks peruses the fashion jewellery counters with her aunt. “I didn’t think it was that common,” says the 26-year-old of the prevalence of treated gemstones. “Mostly you pay for what you get, but businesses need to tell people what they are buying,” she adds.

Certainly the lower prices paid for treated gemstones typically reflect their value. “You’re not necessarily getting ripped off, the problem is in the understanding. I can see that it’s a challenge for jewellers if you give too much information people go, ‘Oh hold on, I don’t want that, I want a natural one,’” Ms Griffith says. “I don’t have a problem with treatments as long as they tell people and it’s sold at what they are worth.”

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