Monday, May 16, 2016

Gemstone Treatments: How acceptable are they?

The issue of gemstone treatment has become a critical and fairly controversial topic in the gems and jewellery Industry. On one hand, they improve the appearance of many commercially important gems like rubies, emeralds, sapphires, tanzanite, etc. which makes these gems more affordable and marketable to the consumers. For instance, today most emeralds are fracture-filled, most rubies and sapphires are heat-treated. Without treatment, the supply of these gems would be a fraction of what it is today and those available would be very expensive. On the other hand, the absence of treatment makes many rubies, emeralds and sapphires more valuable that treated ones as just like flawless and VVS diamonds they are rare which also makes them very expensive.

Types of treatment:
Some commonly used treatments are:
·         Heat Treatment- Gems are exposed to rising temperatures to change appearance by enhancing or removing color, to create or remove inclusions or to create phenomena like stars in Star Rubies and Sapphires. Heat treatment is very desirable in gems like Tanzanite which is an unattractive brown color before treatment and turns into a vibrant blue or purple after heating.
·         Fracture-filling- In Fracture filling a gem's fissures or fractures are filled with a colorless substance whose refractive index is close to that of the gem which makes the fractures less visible. Today most Emeralds need some sort of filling to make them more marketable and commonly used fillers are oils, polymers, resins, etc.
·         Lattice Diffusion- In lattice diffusion, the gem is treated to a temperature close to its melting point in presence of color-causing elements like chromium, iron, beryllium, etc. The high temperatures cause these elements to penetrate the gem. It is used on pale Sapphires which are heated in the presence of iron and titanium oxides to deepen the blue color.
·         Irradiation- In Irradiation, the gem is exposed to electromagnetic radiations to improve or remove color. This color is usually not stable, so the gem is heated in a controlled environment (Annealing) to make it stable. For instance, pale tourmalines can be irradiated to a dark pink color. The color is as stable as a naturally-colored tourmaline and the treatment is not even detectable.
·          Dyeing- Dyeing, addition of colors, is one of the oldest gem treatments. It is used on porous gems such as Lapis Lazuli, Turquoise and Coral or gems with surface-reaching fissures which can accept the dye. If a gem doesn't have surface reaching fractures, it can be quench-crackled and then dyed. For example, colorless quartz is quench crackled and then dyed green to imitate emerald.

Disclosure of treatments: The Right thing to do
Although trade generally accepts some form of treatments, for example heating in Rubies, fissure filling with oil in Emeralds but some treatments like dying with colored oils, filling fissures with epoxides aren't well received. Today consumers are becoming more and more aware and they want to know whether the gems are treated or completely natural. In such a scenario, the right and ethical way is to fully disclose the treatment or treatment suspected in the gem. There are some treatments which are permanent and undetectable even with advanced techniques, therefore the customer should be fully informed about any suspected treatments as well.
To know more about types of treatments, synthetics and how to detect them, visit the, they have various courses available to train those who want to make an impact in gems and jewellery indusrty.

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