Gemstone Irradiation: Keeping Workers and Consumers Safe

By carefully exposing crystals to controlled amounts of ionizing radiation, industry workers can induce changes in their molecular structure that result in a more intensive colour. This happens when the irradiation causes electrons in the gemstone to be ejected from their positions in the crystal lattice, subsequently changing the pattern of light absorption.

Irradiated diamonds, sapphires and topazes, like other gemstones, can be found in intense hues of blue, green, pink and other colours, often a significant enhancement from their paler shades when mined from the ground.

Immediately after irradiation, these stones can contain activated residual radioactive material at dose levels that need to be carefully controlled to keep jewellery industry workers and consumers safe. It is important to have effective regulatory oversight for the radiation protection of those involved in the manufacturing and trading of these gems.

“Irradiated gemstones may need to be stored to allow the radiation levels to be reduced before these gemstones can be further processed or used by the public,” said Miroslav Pinak, Head of the IAEA Radiation Safety and Monitoring Section. “The IAEA has published safety standards that guide countries on authorization, regulation and justification of the manufacturing and sale of irradiated gemstones and other consumer products that contain radioactive material.”

Rough gemstones can be irradiated at various stages of cutting, from completely uncut ones to cut and polished ones, which are ready for mounting on a necklace, for example. Typically, the gemstone wholesaler  arranges for irradiation to achieve the desired colour enhancement. The gemstones are then kept for a period of time at the irradiation facility until the radioactivity has naturally decayed to safe levels, as specified in the IAEA International Basic Safety Standards or by the national regulatory body.

If there is no adequate regulatory oversight, the irradiated gemstones can potentially result in relatively large radiation doses, which can impact primarily the skin, with the possibility of skin burns. Therefore, regulatory oversight is vital to ensure that gemstones are carefully handled and prepared for purchase by following regulatory processes and guidance for irradiated gemstones.

If a country chooses to produce and trade irradiated gemstones, the IAEA advises the country to use IAEA safety standards, which describe how an effective quality assurance and verification programme should be established and implemented by the irradiation facility. This is aimed to ensure that gemstones with activity concentrations above regulatory limits are not provided to the public directly after irradiation, to wait until it decreases and to ensure that specific batches of gemstones are traceable. Methods include batch labelling, assessment of activity concentrations of specific radionuclides, calculation of decay and release times, and secure storage arrangements and release criteria.

“Ensuring the safety of consumer products that utilize or emit radiation for their functional operation is a regulatory requirement. As regulators, it is essential that we stay ahead of what is happening in the industry, anticipating challenges, and developing robust frameworks that not only react to current risks but also anticipate future ones,” said Igor Gusev, Senior Expert at the Saudi Arabia’s Nuclear and Radiological Regulatory Commission. “Our goal is not merely to manage radiation safety but to define and embody best practices that ensure the safest possible use of these technologies”.

The IAEA guide on Radiation Safety for Consumer Products, co-sponsored by the Nuclear Energy Agency of the Organisation for Economic Co-operation and Development (OECD), assists countries in the safe manufacture and supply of gemstones and other consumer products that contain radioactive materials, like ionization chamber smoke detectors, tungsten welding electrodes and high-intensity discharge lamps, in line with the IAEA General Safety Requirements. This allows countries to maintain an adequate level of control, prevent the sale of consumer products produced in practices that are not justified, while not unnecessarily obstructing the sale of consumer products produced in justified practices.