Treat or Treat

Gemstone treatments: are they a trick or do they work a treat? Kerry Gregory of Gemmology Rocks has the answers.

Trick Treat? or

How?

There are numerous gemstone treatments, and they vary hugely in complexity of process and identification. They range from crude and simple processes, like painting, coating, dying or foiling gemstones, to more complicated heating and filling processes, then more time- and resource-consuming processes, like diffusion or irradiation. Many modern treatments are still carried out the way they were thousands of years ago, for instance heating a gem in a ball of dung. Many are complicated multi-stage processes involving a number of steps, pieces of equipment and additives. Understanding how gems form, the science behind colour and other properties helps gem treaters work out ways to create changes in the starting material. It’s also essential for any of us at the back end trying to identify treatments. Often the cruder or simpler the treatment, the easier it is to spot, and, conversely, complex and modern treatments often need complex and modern methods to identify them as well.

Why?

Why are gemstones treated? There are several reasons – some good, some bad, in my opinion. Some gem treatments were discovered by accident; there are many

In my last feature for The Jeweller, I discussed the importance of knowledge and disclosure, and the prevalence of gemstones on the market being sold without either. Now we’re taking a closer look at just one facet (pun intended) of gemstones: treatments. Are they all bad?

Are they all tricks? To answer the question, we need to look fully, from a few angles, to gain all the information and test the subject – just like with any gemmology. In my opinion, like most of gemmology, it’s not a simple, yes or no, right or wrong, this or that, answer.

What?

To start at the beginning – what is a gemstone treatment? Quite simply, it is any process carried out on a gem material other than simple cutting, polishing or fashioning. Gemstone treatments are not a new or modern thing; as long as we’ve had gemstones, we’ve had gemstone treatments, ways in which we alter their appearance and properties. Gemstone treatments are well documented, in terms of what and how they were carried out, in historical texts 2,000 years ago. There are finds of treated gemstones from at least as early as 1300 BC. Dr. Kurt Nassau covers this subject wonderfully in his book Gemstone Enhancement (1984) and in a GIA article ‘The Early History of Gemstone Treatments’ of the same date, if you want to delve more into this fascinating subject.

Did you know almost all blue topaz on the market is irradiated?

apocryphal stories about gems falling into fires or ovens, buildings burning down, stones or chemicals being mixed in containers used for treatments, cutting or repair, and other ‘accidents’ that caused gemstones to look different (usually better!) than they did before.

These accidents prompt a realisation that change can happen on purpose, too. Many treatments are a result of years of research, experiments and trial and error. A good friend of mine, a peridot dealer (a stone which is notoriously difficult to treat) is dreaming of the day someone comes up with a way to improve the material, because then he’ll be able to use and sell more of it, and for higher prices.

This is the crux; treatments primarily add value to a product. You wouldn’t spend time and money doing something to your product to devalue it – people seem to think treated gems are worth less than untreated gems. This is simply not true; effective treatments always add value to a product. What is true is an untreated gemstone will be of higher value than a gemstone that looks the same but has to be treated to achieve that.

So, treatments are not necessarily designed to deceive, but absolutely, and throughout history, many treatments deceive a buyer into believing a stone is a better quality, more valuable or even different stone entirely, to make them more willing to part with considerably more money for this improved stone than they would have before the treatment. However, in reality, if it weren’t for gem treatments, we might not have any gemstones, and we certainly wouldn’t have the range of colours, sizes and price points we can currently choose from.

Many common commercial gemstones are routinely and commonly treated. Almost always, ruby and sapphire are heated, emerald is filled, turquoise is stabilised and blue topaz is irradiated. This is to either improve colour, clarity or durability, and desirability of the gem – or all three. It’s often a simple case of economics. Most mines, regardless of mining technique, produce a range of material qualities. Whether panned for in rivers or dug out of the ground, most gems are discarded as rock, dirt or gravel. Even that material that can be used for something, ordinarily a huge percentage will be used beyond the gemstone industry.

The vast majority of gem production will be low quality commercial material, with a small amount of good quality commercial material, a tiny amount of high-quality gems and a minute proportion of fine goods. Finding a way to use the low quality material means being able to afford to get out, use and sell the high quality stuff. It’s very uncommon that gems come from the ground in beautiful, highly saturated colours, with high clarity, unincluded and unfractured or fissured – those that do are incredibly desirable, valuable and rare.

The rest need a little help to look their best. Many humans enhance their natural features with make-up, dyes, clothes. We paint, wax, fill ourselves to look better and last longer! Similarly, we treat lots of natural products to make them prettier and more durable. Wool, cotton, leather, wood are regularly dyed, painted, waxed, impregnated to change their colour and make them suitable for everyday functions and make them last longer. It makes sense, doesn’t it? It also makes sense for gemstones – so why are people horrified by the thought?

So is it good or bad?

Whether a treatment is a good or a bad thing comes down to knowledge and disclosure. I think gemstone treatments are brilliant – they give us the opportunity to maximise these natural resources. They give an otherwise unsaleable allure and value, offering consumers choice and businesses more chances to thrive as long as everyone in the chain a) knows what they’ve got and b) tells each other openly and honestly what it is. As long as everyone has the choice and information they need to make a decision, i.e. they know what’s happened to their gemstone, and they’re OK with it, treatments are not bad. Only when this doesn’t happen is it bad.

What should you do?

As a professional, you have a responsibility to know what you’re buying and what you’re selling. That means keeping up to date with the market, with treatments, with identification – you cannot spot what you’re not looking for. You can manage this by buying from only known and trusted sources and having a robust chain and assurances from suppliers. You can manage this by ensuring you send everything you buy to a laboratory for checking – if you have the time and money – or testing everything in-house if you have the knowledge, skill, equipment and time. Sometimes you can use a combination

of these and spot check a percentage of purchases from each source.

In terms of disclosure, as an industry we follow CIBJO guidelines to discuss, define and disclose gemstones. The rule is all treatments must be disclosed. You must tell your customer about all and any treatment on their gemstone. How you are supposed to do that differs depending on the stone and treatment (see summary table). Some treatments require only ‘general disclosure’ – you just need to informally make the customer aware of the treatment, in conversation, as part of a description or a footnote on an item, for example. This is usually for traditional treatments, like colourless waxing of jadeite, heating of corundum and other gems or oiling of emeralds.

The majority of treatments, however, need ‘specific disclosure,’ meaning in theory the treatment must form part of the description of the item, immediately preceding the gemstone name, be as conspicuous as the gemstone’s name and be in all descriptions and on sales paperwork for the item. In practice, this rarely happens. How many items do you see described as ‘irradiated blue topaz’ for instance, in windows, on websites or on sales receipts or invoices? Don’t shoot the messenger, I don’t have all the answers to this because it is an incredibly complicated subject. What I do know is we all want to do our best, so we need to work to make this work!

In a future issue, I’ll outline the common treatments in the market, what to look out for and ways you might start to recognise these if you come across them.

General Disclosure Treatments Specific Disclosure Treatments

Requiring you to informally tell your customer about the treatment, e.g. in conversation, or as part of details about an item online You must use the word treated or the treatment in conjunction with the gem name in every description and in any documentation about the item, e.g. “treated ruby” or “irradiated topaz”

Treatment Description Common examples Treatment Description Common examples

Heating Heat only without additives ruby, sapphire, aquamarine, morganite, citrine, green quartz, amber, demantoid garnet, kunzite, tourmaline, tanzanite, zircon

Surface waxing Surface colourless waxing as part of the fashioning or finishing process

Oiling Oiling or fissure filling that does not change the colour

Bleaching Use of chemicals to remove dirt, debris and dark patches

jadeite, malachite, coral, lapis lazuli, turquoise

emerald, Paraiba tourmaline

coral

Irradiation e.g. blue topaz Coating e.g. “mystic” and other topaz Diffusion treatment e.g. beryllium treatment of sapphire Fracture filling e.g. diamond, ruby Impregnating e.g. turquoise, opal Dying e.g. jadeite, quartzite Coloured waxes e.g. corals

Diamond treatment Any treatment whatsoever on diamond must always be disclosed Laser drilling, fracture filling, irradiation, HPHT

Pearl treatment Aside from bleaching all treatments on pearl must be disclosed Heating, oiling, waxing, lustre enhancing, heavy working

Coating

Diffusion

Dying

Filling

Any substance as a layer over the outside or part of the outside of a gemstone

Diffusion of outside chemical elements into a gemstone to enhance colour or optical effects

The use of dyes or other substances to alter the colour of a gemstone

Using material to fill cavities, fractures or fissures in a gemstone

Impregnation Permeate a substance throughout a porous material

Irradiation Change of colour of a gemstone through bombardment with irradiation

topaz, quartz

ruby, sapphire, green topaz

coral, jadeite, lapis lazuli, opal, polycrystalline quartz

emerald, ruby, sapphire, Paraiba tourmaline

coral, jadeite, opal, turquoise

blue topaz (almost always), morganite, heliodor, smoky quartz, other coloured quartz, kunzite, zircon