What's the difference between natural and cultured pearls?
Natural pearls, just as the name implies, are formed when irritants enter the oyster by accident. This is a pretty rare occurrence and doesn't result in many jewellery quality pearls being available.
About 100 years ago a Japanese pearl farmer developed a process whereby a small piece of shell could be inserted into living Akoya oysters. These oysters were then put back into the water and the pearl forming process began. Today cultured pearls account for the majority of pearls used in jewellery.
Types of Pearls
Akoya pearls are primarily grown in the cool to temperate saltwater of Japan (China is the second largest producer) in the Pinctada fucataoyster species. This temperature allows the pearl to develop highly uniform mineral crystals resulting in brilliant lustre. Thus, many experts believe Akoya pearls have the highest lustre of all types. It takes between 8 and 24 months for a pearl to grow, although most farmers wait at least one year in hopes of a larger pearl. The size can range from 2 to 10 millimetre (average size is 6-7mm) and the colours are rose, silver/white, cream, gold and grey/blue.
Tahitian pearls are grown in the Pinctada margaritifera cumingi oyster species (also known as the Black Lipped Oyster) found throughout its native waters of French Polynesia. Only 1 in 10,000 of these oysters produces a pearl and because of this rarity they cannot be mass produced. It takes 22 to 26 months for a pearl to grow and the size ranges from 8 - 18 millimetres (average size is 9-10mm), but there are sometimes extremes; the largest Tahitian ever found was 25 millimetres! Tahitian pearl colour includes peacock (the most popular), black/black, black/grey, silver/grey, black/rose, black/blue, black/green and aubergine (eggplant).
South Sea Pearls
South Sea pearls are grown in the warm, pure waters off of Australia, Indonesia, the Philippines, Myanmar and Thailand in the oyster species Pinctada maxima (the two varieties are known as the Silver Lipped and Gold Lipped Oysters). These pearls (and their shells) are the largest and rarest grown. It takes 20 to 24 months to grow the pearl and there are many complications that can cause them to die. South Sea pearl size ranges from 9 Ã¢â‚¬“ 20 millimetres (average size 13mm) and their colours include silver, silver/pink, white, white/pink, white/gold and gold.
Freshwater pearls are formed in lakes, rivers, ponds and other freshwater bodies mainly in China (Japan and the U.S. also produce). Up to 40 pearls can be grown at once in one mussel (such as the Hyriosis cumingi) and for a long time there was much emphasis on producing large quantities, but today science has improved the farming techniques resulting in higher quality freshwater pearls. It takes 3 to 7 years for the pearls to grow and their size ranges from 3 - 13 millimetres (average size is 6mm). Freshwater pearls come in a variety of pastel shades including white, pink, peach, lavender, grey, yellow and cream.
Care Of Pearls
Because pearls are very soft and need special care they never should be tossed on top of or next to other gems in a jewellery box; store them in a jewellery pouch.
Besides being soft, pearls are easily damaged by chemicals like perfume, vinegar, and lemon juice. Heat can turn pearls brown, dry them out and make them crack. Dry air can also damage pearls. Most safe deposit vaults have very dry air and can damage pearls.
Some tips on caring for your pearls:
Special thanks to Imperial Pearls and GIA.
- Only use jewellery cleaners labelled as safe for pearls.
- Never use an ultrasonic cleaner.
- Never steam-clean pearls.
- Never use (or expose pearls) to dish or wash detergents, bleaches, powdered cleansers, baking soda, or ammonia-based cleaners (like Windex).
- Never use toothbrushes, scouring pads or abrasive materials to clean pearls.
- Do not wear pearls when the string is wet. Wet strings stretch and attract dirt, which is hard to remove.
- Do not hang pearls to dry.
- Take your pearls off when applying cosmetics, hair spray, and perfume, or when showering or swimming.
- Avoid wearing pearls with rough fabrics like Shetland wool.
- Have your pearls restrung once a year if you wear them often.