In every 10,000 oysters, you might be lucky enough to find a single natural pearl. Because of this scarcity, most pearls today are cultured pearls. A tiny bead is implanted in an oyster, so that it is gradually coated in layers of a beautiful, pearlescent substance called ‘nacre’ which build up to create a lustrous pearl.

SOUTH SEA PEARLS
South Sea pearls are the largest and the best quality pearls in the world. The pearls generally range in size from 10mm to 15mm and can grow to be as large as 20mm but these are considered extremely rare and valuable. The reason they grow so large is due to the size of the Pinctada maxima oyster, commonly known as the 'Silver Lipped Mother of Pearl Shell'.

Almost three quarters of the world's Pinctada maxima shells grow in beds that lie off the untouched coast of North West Australia within a 200km radius of Broome. It is these clean and warm waters that provide the ideal environment for pearl production. Once the shells are collected technicians carefully insert the nucleus - a polished sphere made from the American freshwater Pig-Toe mussel shell from the Mississippi river. This has been found to be the most successful substance as nucleus, as it has the same specific density as the shell nacre and is less likely to be rejected.

The shells are then transported to the pearl farms and are suspended from culture systems - many of them in isolated bays. The locations are chosen for their geographical protection from cyclones (October - March) and for the quality of the microscopic phytoplankton which abound in the waters. For the next 20-24 months, daily intensive husbandry is required by farm workers to help maintain the shell in prime condition so that hopefully it will produce a pearl of great quality.

South Sea cultured half-pearl (mabe pearls)
Otherwise known as a 'mabe pearl', the cultured half-pearl forms on the inside lip of the host shell. Instigated by a hemispherical nucleus, it is attached to the inside lip of the shell which secretes nacre in its normal process. Once removed, it is then backed with mother of pearl. These pearls are often used for earrings (particularly clip on) and pendants.

South Sea keshi pearl
These are small pearls that have no nucleus. They are natural pearls grown whilst the shell has been in the care of a pearl farm, forming the same way a pearl would have developed in the wild. These pearls are wonderfully irregular in shape, as they are solid nacre. They are extremely rare but because of their size (generally 2mm to 10mm) they are less expensive than the larger South Sea pearl.

TAHITIAN PEARLS
The Tahitian pearl is also part of the South Sea pearl family and are  produced from the black lipped Pinctada margaritifera shell (commonly known as the 'black lipped oyster') in the remote lagoons of French Polynesia in the South Pacific. In addition to black, Tahitian pearls can throw pink, blue, gold, silver and reddish purple or 'aubergine' tones. The colour of the pearls vary with the oysters genetic background, the way the "seed" is put into the oyster, the minerals in the water and the quality of the plankton absorbed by the oyster. Tahitian pearls range from 8mm and can grow as large as 16mm - they are valued similarly to the Australian South Sea pearl.

AKOYA PEARLS
Akoya pearls are made from the Pinctada Fucata oyster and are predominantly farmed around the islands of Japan. It was the Japanese who pioneered the farming of pearls in the early 1900's. These pearls generally start at 6mm and it is unusual for them to grow above 9mm in size.

FRESHWATER PEARLS
Freshwater pearl farming has been rapidly developing since the mid 1990's in mainland China. Instead of using oysters the pearl farmers use mussels and as their name suggest are grown in huge freshwater lakes. The size range is similar to the Akoya pearl and due to their relative ease of cultivation, freshwater pearls are less costly.

CRITERIA
There are 5 basic criteria used to evaluate a pearl:

LUSTRE - Lustre describes the beauty of light being reflected from the surface of the pearl and simultaneously refracted from inside the pearl nacre. Lustre is a subdued iridescence, as opposed to the glittering brilliance of a diamond, and is the most important factor in determining the quality of a pearl and has a large impact on its value.

SIZE
The larger the pearl the scarcer it is and hence becomes more valuable. Measured across the smallest diameter a pearl's size can range from 2-3mm (seed pearl) through to 20mm (South Sea pearls). Pearl size is the result of the size of the implanted nucleus plus the thickness of the nacre, which grows layer by layer. It is the size of the pearl (combined with its lustre) that has the largest impact on its value

COLOUR
Colour does not affect the quality of a pearl, but does affect its perceived beauty according to each individuals taste. The major classifications are white, pink, silver, cream, gold and black though some pearls will also have a secondary colour - usually rose, green or blue - around the outside of the pearl. The most highly prized are pearls that display an unusually beautiful orients of coloured overtones such as white pink, silver pink and deep gold.

SURFACE
As pearls are created by nature, it is rare to find them free from any surface blemishes. These are natural characteristics of real pearls making each one unique and individual. However, when found, a flawless surface will increase the value of a pearl significantly.

SHAPE
Perfectly round pearls are the most scarce which places a premium on the price. Other shapes though have their own unique charm and value and are often preferred depending on individual taste. Pearls are found in an array of shapes and sizes including round, semi-round (mabe), button, circled, oval, drop, semi-baroque and baroque.

PEARL CARE

SOFTNESS MAKES PEARLS VULNERBALE
With special attention and care, your pearls will last a lifetime. Keep them away from household chemicals such as hair spray, makeup, and perfume which can dull their lustre over time and cause spots and blotches. To avoid the effects of cosmetics and perfume, pearls should be the last thing a woman puts on before going out and the first thing she takes off after returning home. Also, pearls are quite soft, so for the longest-lasting pearls choose those with thick nacre that can help them with stand wear over time.

FREQUENT WEAR IS BEST
The best way to care for pearls is to wear them often because the body's natural oils keep them lustrous. Pearls should be wiped with a soft cloth before being stored and kept separate from other precious metals or gemstones that might scratch or dull their tender surfaces.