Pearl Treatments

Pearls are nearly always processed in some way nowadays. After harvest, white pearls are bleached to improve their colour and all pearls are polished so that they look their best. A pearl treatment is altering the pearl's appearance in any way other than polishing.


Low quality pearls can be subjected to up to three different pearl treatments, these are dyeing, irridation and lustre enhancements. This is often the most economical thing to do with these pearls, as the other options are to throw it away, sell it at a heavily discounted price or strip and sell the nacre to re-use the nucleus.


In dyeing, silver nitrate (or a different organic chemical) is used to darken the nacre of the pearl. In irridation, gamma rays are used to darken the nucleus of an Akoya pearl or the nacre of a Freshwater pearl. The final treatment, lustre treatment, involves the pearl being heated and cooled, or being coated with a substance not dissimilar to clear nail varnish to enhance the lustre, although this is not a common treatment and is generally frowned upon; like nail varnish it will gradually chip or peel away, leaving an undesirable, low-lustre pearl underneath.


The technique of using silver nitrate to darken the pearls has been used for many years, it causes a chemical reaction with hydrogen sulphide and light as it penetrates the layers of nacre and creates a deep black colour. Farmers can also use other chemicals, organic or inorganic, to create other colours. It is not uncommon to see Freshwater pearls of a variety of colours, and Akoya pearls can be 'pinked', which produces a pretty rose overtone.


Irridation affects freshwater and saltwater pearls differently, as the gamma rays don't affect the nacre of a saltwater pearl and only darken the nucleus. In freshwater pearls, the nacre is affected and can become very dark, even with an intense metallic sheen. Irridated Akoya pearls usually look blue or grey.


Some treated pearls are easy to spot, such as the brightly coloured Freshwater pearls (an example of this can be seen here) You could also have a look down the drill hole of a pearl (if it has one) to see if the nucleus is a darker colour; this is a good indication of a saltwater pearl that has undergone irridation.


A pearl being treated is not a bad thing, unless you are specifically looking for untreated natural pearls and are prepared to pay more for them. Our pearls state whether they are natural colours or produced through pearl treatments, so you know exactly what you're paying for.





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