Pearls are synonymous with ‘white’ colour. The image of white pearls is fixed in our mind that many of us aren’t aware about the other colours that are available. While white is the quintessential colour of pearls, coloured ones are unconventional and make a person stand out from the crowd. The colour of a pearl is a combination of its body colour and colour of its overtone.
Overtone is the colour reflected by a pearl. The overtones are usually pink, purple, green or blue. Some pearls exhibit iridescent phenomenon with changing shades when altering the position of it or altering the light conditions. Check out this site for pearl jewellery in a plethora of colours.
Factors what determine the colour of a pearl:
The colour of a pearl is determined by a couple of factors but luck plays an important role. Few general rules of the thumb are:
- Black-lipped oysters usually produce black, deep peacock, charcoal and silver pearls.
- Black pearls are very rarely produced by other types of oysters.
With the exception of these rules, there is no way to guess the colour of the pearls harvested.
- Conchiolin layer
The microscopic pigments of the conchiolin layer are partly responsible for the colour of pearls. Conchiolin serves as the glue that holds the aragonite layer together. If the conchiolin layer is pigmented by a particular colour, like blue, green, yellow or grey, this pigment is visible through the thin aragonite layers and leaves the pearl with a particular hue.
- Aragonite platelets
These platelets are semi-transparent and hexagonal shaped accounting for the prismatic layers of pearls. When white light hits the pearl surface, a light beam is refracted back at those viewing the pearl. This phenomenon is responsible for the overtone of the pearls. Golden Sea pearls for instance have the golden shade in varying intensities. The overall colour visible to a naked eye is the iridescent faint colour on the pearl’s main body.
In other cases, some treatments and dyes are employed to produce pearls of a particular colour so as to meet market demands. Well-treated pearls have metallic shine and an even colouring.
