30th Wedding Anniversary Gift
Pearls are an organic gem material. They form inside oysters (saltwater pearls) or mussels (freshwater pearls)
There are three types of ‘pearls’:
Natural Pearl: This is where an irritant such as sand or a parasite has entered the mollusc causing it to secrete layers of nacre (calcium carbonate) to build up around the irritant to smooth it and therefore, form a pearl.
Natural pearls are rare today due to the amount of pearl fishing over thousands of years which has rendered the natural pearl beds near empty.
From the 16th century, many natural pearls were found in Mexican, Central American and Venezuelan waters.
Cultured Pearl: The pearl forms in exactly the same way, by a build-up of layers of nacre.
The difference is that the irritant to start the process is initiated by man, either using just a piece of the mantle tissue from a ‘sacrificial’ mollusc (this is often done for freshwater cultured pearls in mussels) or, in the case of saltwater cultured pearls, a mother of pearl bead is gently inserted into the host oyster.
Simulated/imitation: These are NOT pearls of any kind. They are beads, sometimes glass, plastic or shell and they have a ‘pearlescent’ coating put on them so that they look like a pearl. With age, these coatings wear/flake off.
Saltwater cultured pearls localities:
Akoya: Mainly from Japan and China.
South Sea: Northern Australia and Indonesia and Southern coastal areas of South East Asia.
Black Tahitian Cultured pearls: Gambier Islands and Tuamotu Archipelago waters of French Polynesia.
Freshwater cultured pearl: These are mainly farmed in China.
Farming Akoya, Tahitian, South Sea and Freshwater Cultured Pearls:
Before the pearl can start growing, the pearl farmer needs to care for the mollusc once the irritant has
been inserted to ensure that it is in the best possible condition.
With the Tahitian and South Sea oysters, this care time can be up to three months, Akoya oysters about six weeks and freshwater mussels just two weeks.
Many factors influence the growth rate of a cultured pearl, not least the cleanliness of the water they are farmed in, the temperature and even the time of year. Whilst they’re growing the pearl farmers check on the molluscs to make sure of their health and to remove any parasites.
The nacre on the pearls grows at varying rates and can be up to 5mm per year for Chinese freshwater cultured pearls, whereas Akoya pearls grow at approximately 0.3mm per year and up to 2mm per year for the Tahitian and South Sea pearls.
As an average guide, it can take 2 years for a freshwater cultured pearl to reach 9.00mm in diameter, Akoya cultured pearls 10 – 14 months to get to 9.00mm diameter, Tahitian cultured pearls 18 – 24 months to grow to 10.00mm diameter and South Sea cultured pearls 2 – 3 years to grow up to 15.00mm diameter.
How many pearls grow at a time?
Akoya oysters have one or two pearls grow and when they are harvested the oyster dies.
With the Pinctada Maxima oysters used for producing the South Sea pearls, only one pearl is produced at a time but as they do not die when the pearl is harvested they can be used several times. If a particular oyster produces very good-quality pearls it will often be returned to the wild so that its genes may be carried on.
Freshwater cultured pearls are produced in greater numbers per mollusc.
The average is in the 20s although it has been known for more to be produced.
The fact that more freshwater cultured pearls can be produced per mollusc is one reason for their lower price. Also, many freshwater cultured pearls are not as completely spherical as saltwater pearls but the rounded shape is becoming more ‘normal’ in freshwater cultured pearls these days. In the past, freshwater cultured pearls were often referred to as ‘rice pearls’ and the slightly larger, smoother oval ones as ‘potato’ pearls due to their shape.
Harvesting:
Cultured pearl harvesting takes place in the spring. This is because the colder water produces a better layer of nacre meaning that the outermost, visible layer is of excellent quality.
Determining the quality of a pearl involves a number of factors:
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- The thickness of the nacre so that the pearls will wear well.
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- Surface blemishes – the fewer the better.
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- Lustre – The best pearls have high lustre with reflections on the surface.
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- Size – 2mm – 16mm depending upon the type of mollusc and the size of the irritant used.
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- Shape – perfectly spherical pearls are most highly sought after, although some ‘drop’ shapes are also popular.
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- Colour – white/cream are the most popular and traditional. However, grey, pink, gold and purples show some popularity.
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- Match – for earrings or a strand of pearls it is important that the pearls match for colour/size or complement each other otherwise the value of an item could be compromised.
Cultured Pearl Jewellery:
Many types of jewellery are available today with pearls either the main component or as an accent to other gems. Here at Gerry & Co (Jewellers) Ltd we try to stock a good range of both freshwater and Akoya cultured pearls in plain or knotted strung necklets, earrings and bracelets. We can also make enquiries with our suppliers if there is something particular that you are searching for or, we can ask our workshop to create an item to your specifications which can take some time as we would first have to source the gems for the project.
Care of your cultured pearls:
Pearls are a fairly soft gem material and are also susceptible to damage from acid in the skin and sprays such as perfume and hairspray. For this reason, you should apply any sprays at least 30 minutes before putting on the pearl jewellery to allow the spray to dry completely and reduce the damage it can do to the pearls.
In order to keep your pearls in the best condition it is advised that they should not be stored with other jewellery to avoid being scratched, and cleaned with a soft damp cloth after wearing. Do not put them to soak in water as if it is a pearl necklet this could cause the thread to stretch and become worn and at risk of breaking or if a ring or earrings with a pearl that is cemented in place it could soften the cement and cause the pearl to detach from its post.
Periodically it is good to check that thread is still tight and secure, with no loose threads poking out and that if the item has claws, check that they are safe and that no pearls feel loose in their settings. If you notice any of this then please bring them to us so that we can get them to our workshop for repair.
A lovely quality pearl item is a classic piece of jewellery which, given the correct care and attention will last for many, many years.
Pearls are beautiful alone but they are also stunning when seen with other gemstones. Please look at our other posts for information on some other gemstones:
Diamond – April Birthstone
Ruby – July Birthstone
Aquamarine – March Birthstone
It is important to look after your jewellery and keep it clean and safe. Please see our post on this:
Care and Cleaning of Your Jewellery
