Colour Gem Master Card

Rubies, on the whole, are very durable stones and are safe to use in jewellery dips and ultra-sonic cleaners, however avoid using heat with untreated stones as this could affect the colour and future recertification. Avoid coating with borax before applying heat as borax may eat into rubies and sapphires.

Rubies are increasingly being treated by filling with glass and stones. Rubies that have been treated in this way may contain a very large percentage of glass. If you become aware that you or a customer has such a ruby, avoid direct heat, acids, ultrasonic and steam cleaners, knocks and blows.