When most people think of pearls, an image of a classic white pearl strand comes into their mind. But do you know that pearls are not only white? In fact, one of the pearls’ most striking qualities is their stunning natural colours.
From white, cream, pink, yellow, green, blue to black, there are so many shades in between. So what causes a pearl’s colour? And what should you be aware of when buying pearls?
What Causes a Pearl’s Colour?
Many factors, such as the type of the host oyster, the inserted mantle tissue piece, nacre thickness and quality, and the oyster’s environment, can all influence the colour of a pearl.
But the No.1 factor that determines a pearl’s body colour is the type of its host oyster. For example, dark colours such as grey, purple and black seen in Tahitian pearls, only naturally occur in black-lipped oysters. Golden pearls only grow in P. maxima oysters that are native to the warm waters of Australia, Indonesia, the Philippines, and Burma.
In addition to the body colours, pearls often display delicate overtones and beautiful orient.
Natural Colours in Different Types of Pearls
- Freshwater pearls – White, Cream, Pastel Colours Apricot and Lavender
- Akoya pearls – White and Cream with Pink and Green overtones
- South Sea pearls – Golden, Yellow, White and Silver
- Tahitian pearls – Dark Colours including Aubergine, Blue, Green, Grey, Black, Purple, Peacock, and Pistachio
The quality and thickness of nacre can also affect a pearl’s colour. Nacre is the substance that forms a pearl. Its quality and thickness directly affects the lustre and surface quality of a pearl. If the nacre is thin or of poor quality, the pearl will appear dull and lack overtones.
The aquatic environment of the host oyster including nutrient level and trace elements can all contribute to the colour of a pearl. Sometimes, a pearl’s colour can also be affected by the mantle tissue piece inserted from another donor oyster during the nucleation process. Pearl farmers and marine biologists have been trying to figure out ways to influence the pearl colour. But the exact reasons that cause pearls to have different colours continue to remain a mystery.
Pearl Buying Tips
Generally speaking, pearls with natural colours are more valuable than those that are colour treated. In 2012, a natural grey pearl necklace was sold more than $3.35 million at Christie's London auction (JCK). Exotic colours such as aubergine, peacock, black, brown, and purple in Tahitian pearls, are the most treasured colours. For South Sea pearls, the most prized colour is golden. The high-value colours for Akoyas are silver and white with pink or green overtones. For freshwater pearls they are lavender and white.
There are a couple of tips that are worth bearing in mind when you buy coloured pearls. Don’t be afraid of asking your retailer about the type of pearls you are looking at. As some colours can only appear in certain types of pearls, you would know immediately that deep colours such as blue, cherry, brown and black in freshwater pearls are unnatural, and are the result of colour treatments.
In addition, if a strand of pearls appear uniform in colours, it is very likely that they are colour treated. Sometimes it may be possible to see residual of dye around the drill holes. If you are in any doubt, do ask your jeweller whether the pearls are colour treated.
It is usually a personal preference when choosing the pearl colour. Dark, exotic colours are a great match for evening dresses or formal wear. Soft pastel colours in freshwater pearls can add a feminine yet sophisticated touch to your outfit. Multi-coloured pearl strands are perfect if you fancy a contemporary and fun look. Or you can always opt for white pearls when you want to achieve chic and timeless elegance!