By Leonie Armin FGA / DGA, In-House Valuer
The oldest known gem, the pearl has been treasured throughout history. Once believed to be divine gifts, they are a symbol of purity, innocence and royalty.
Like a diamond, there are many factors that affect the value of a natural or cultured pearl:
- Nacre (iridescent coating constructed from the substance that mollusks release which forms pearls)
- Luster (the light reflected off the surface and internal layers of nacre)
Whether a pearl is natural (occurring in nature) or cultured (intentionally grown by man) has an effect on each of these factors and therefore a pearl’s worth. For example, nacre is particularly important in cultured saltwater pearls because it is affected by the length of development time (typically the longer the better), and the temperature of the seawater (which also affects the development time of the nacre – the colder the water the slower and denser it is deposited which is regarded as less desirable).
A pearl is a relatively soft material. Because of this, they must be cared for in order to prevent damage:
Pearls should not be tossed on top of or next to others gemstones in a jewellery box. They should be kept in something that will protect them from scratches, such as a pouch or box. As they are a natural material, they are composed of 2-4% water and can therefore become dehydrated if they are kept near heaters or in direct sunlight. Safes or airtight containers can be dry, so if you store pearls within them please ensure you take them out regularly.
Pearls should be the last thing you put on and the first thing you take off. Take care when applying make-up, moisturisers, fake tan, hairspray and perfume. The chemicals and acids within these products can harm pearls. They should also be removed while showering or swimming.
With their softness and low resistance to heat, you should be careful when it comes to cleaning pearls. Many commercial jewellery cleaners are unsuitable for pearls, so always ensure they are safe before using them. Pearls cannot be cleaned in an ultrasonic cleaner, they cannot be steam-cleaned, they cannot be bleached, they cannot be cleaned with detergents, baking-soda or any ammonia-based cleaner. Never use toothbrushes, scouring pads or any other abrasive materials, as they can scratch the pearl’s surface.
Pearls should be cleaned regularly. They can become damaged from perspiration, which is slightly acidic. Over time, this eats away at the pearl nacre. To clean pearls, gently wipe them with a soft cloth or chamois. They can also be washed in water with a mild soap. Special attention should be paid to the areas around drill holes, as this is where dirt tends to collect. Once they have been washed, ensure the pearls are laid out to dry thoroughly before worn again, otherwise the strings will stretch and attract dirt. If in doubt, contact your jeweller for advice.
Having Pearls Strung
With time, the string on pearl necklaces and bracelets can stretch and become weak. They should be restrung about once a year with regular wear. Pearls should be strung with silk and knots should be tied between each one, which would prevent them from rubbing against each other and also cascading should the string break.
- When removing a pearl ring, ensure you hold it by the metal rather than the pearl itself. This will prevent the pearl from loosening or being damaged by oils on your hands.
- Try not to wear pearls with rough fabrics, such as wool. It can scratch them.
- Ask your jeweller to regularly check the condition, string or setting of your pearls on a regular basis – at least annually. They will ensure they are properly cleaned and secure.
- Last but not least, wear your pearls. Pearls thrive when they regularly worn and exposed to the moisture in their environment.