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OTHER COMMONLY TREATED STONES

The following is a list of stones that are nearly always treated in order to achieve the colors that we commonly associate with them. Their treatments are not detectable using standard gemological testing.

Tanzanite: heat-treated to a blue/violet from its natural brown

Blue Topaz: irradiated and heated to greenish blue from its colourless form

Aquamarine: heat-treated to a blue from its natural green-blue colour

Citrine: heat-treated to yellow from purple

Cultured Pearls: bleached to even out the colour

GOLD	SILVER	STONES	HALLMARKING	HISTORY OF GOLD	HISTORY OF SILVER

Disclaimer
Opinions and interpretation of law expressed here are my own. If you stand to lose as a result of any decision based on information here you should seek appropriate legal advice. I give this information freely, and cannot accept any responsibilities for losses you may incur. Nor can I accept responsibility in the unlikely event of inaccurate or misleading information. You alone are responsible for your actions.
Also while much of the information is relevant throughout the EU, I have written with particular regard for accepted practices in the UK.

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