How Do Oysters Make Pearls?
A natural pearl begins its life inside an oyster's shell when an intruder, such as a grain of sand or bit of floating food, slips in between one of the two shells of the oyster, a type of mollusk, and the protective layer that covers the mollusk's organs, called the mantle.
In order to protect itself from irritation, the oyster will quickly begin covering the uninvited visitor with layers of nacre — the mineral substance that fashions the mollusk's shells. Layer upon layer of nacre, also known as mother-of-pearl, coat the grain of sand until the iridescent gem is formed.
Cultured pearls are made in the same way. The only difference is that instead of accidental circumstances, a "pearl farmer" embeds a grain of sand into the mollusk.
How do pearls get their colour?
Although most people will be familiar with the image of a white pearl necklace, these gems come in a variety of stunning colours such black, blue, green, pink, and gold. Although some jewellers will dye pearls to achieve this colour artificially, there are a number of natural factors which affect a pearl’s colour. A few of these include:
● The type of shell. For example, black Tahitian pearls can be found in the Pinctada margaritifera oyster, which has a gray and silver shell, and is the only mollusk to form black pearls naturally. Similarly, Golden South Sea pearls are created by the gold-lipped oyster.
● The thickness of the nacre. The thicker the nacre (and the longer the pearl has been growing), the more vibrant and richer the colour of the pearl. If there is only a thin nacre, the pearl’s colour will be less intense and shiny.
● Irradiation treatment. In this process, the pearl is hit with gamma rays that darken the pearl. For saltwater pearls, this results in a silvery or gunmetal colour. For freshwater pearls, this results in a black pearl with high lustre.
In order to protect itself from irritation, the oyster will quickly begin covering the uninvited visitor with layers of nacre — the mineral substance that fashions the mollusk's shells. Layer upon layer of nacre, also known as mother-of-pearl, coat the grain of sand until the iridescent gem is formed.
Cultured pearls are made in the same way. The only difference is that instead of accidental circumstances, a "pearl farmer" embeds a grain of sand into the mollusk.
How do pearls get their colour?
Although most people will be familiar with the image of a white pearl necklace, these gems come in a variety of stunning colours such black, blue, green, pink, and gold. Although some jewellers will dye pearls to achieve this colour artificially, there are a number of natural factors which affect a pearl’s colour. A few of these include:
● The type of shell. For example, black Tahitian pearls can be found in the Pinctada margaritifera oyster, which has a gray and silver shell, and is the only mollusk to form black pearls naturally. Similarly, Golden South Sea pearls are created by the gold-lipped oyster.
● The thickness of the nacre. The thicker the nacre (and the longer the pearl has been growing), the more vibrant and richer the colour of the pearl. If there is only a thin nacre, the pearl’s colour will be less intense and shiny.
● Irradiation treatment. In this process, the pearl is hit with gamma rays that darken the pearl. For saltwater pearls, this results in a silvery or gunmetal colour. For freshwater pearls, this results in a black pearl with high lustre.