Pearls

Pearl Education

A traditional gift for brides, June's birthdays and the third and thirtieth wedding anniversary, pearls were believed by the ancient Babylonians to have life-giving powers and the ability to restore youth. Even in today's informed age, their allure is timeless. The pearl is unique in the world of coloured gemstones as it's the only gemstone formed within a living creature. It is a treasured gift of the sea, revered for its colour, shape and lustre.
Pearls were so cherished by man that as the sources of natural pearls became exhausted; he learned to cultivate them by implanting an irritant into an oyster.  Today, the majority of the cultured pearls come from Japan, China and the South Pacific. Cultured Pearls come in many different colours, from the palest crème and white to rose, lilac, green, gold, gray, and the dramatic Tahitian black. They also come in many shapes and sizes, and can be acquired in both graduated and uniform strands.

Colour

Mollusks create pearls in a palette of colours depending upon the pearl's body colour, considered the fundamental colour of the pearl. Colours generally range from cream to silver-white, to black. But there are also colour overtones reflected across a pearl's surface.  In fact, the colour of a pearl more often than not is a meld of its body colour and its overtone, just as the term "white-rose" will describe a white pearl with a rosy hue. Akoya cultured pearls are white lustrous pearls with usually cream or rosé coloured overtones.  These are the classic pearls most often used in pearl strands.  Classic Japanese Akoya cultured pearls come in shades of white, the most valuable shade being rosé and white. The other shades are white-rose, silver-white rose, greenish-white rose, and greenish-white. Freshwater pearls come in various pastel shades of white, pink, peach, lavender, plum, purple, and tangerine. South Sea cultured pearls come in shades of lustrous white, often with silver or rosé overtones.  They are larger in size than the Akoya pearl and are also used in the creation of fine pearl strands and ropes. 

Black pearls are known as Tahitian pearls, and come most often in shades of black and grey.  While the Tahitian pearl has a black body colour, it will vary in its overtones, mostly be green or pink. Tahitian cultured pearls differ from other pearls in one important respect.  Yes, they are cultured, as opposed to natural, but their black colour is naturally produced by the oyster, which makes them "naturally black" cultured pearls. Colour does not affect the quality of a pearl, but does affect the perceived beauty of the pearl in the eye of the beholder.  Some colours have become more popular than others in particular markets.  For example, white pearls are the most popular in America, while silver are more sought after in Asia. This regional colour preference usually has something to do with the skin tone of the wearer. Most jewellery experts agree that a buyer's colour choice should be primarily based on what will look good on the person who will wear the pearls. In general, pink pearls look best on fairer skin tones, while yellow or golden pearls look best on darker skin tones.

Lustre

When a mollusk senses an irritant within its body it secretes layers of semi-opaque calcium carbonate called nacre (NAY-ker) to coat the irritant.  This substance builds up over time and becomes a pearl.  The thicker the nacre is, the more lustrous the pearl will be.  Though there are exceptions to that rule, the amount of nacre determines the reflective quality of the pearl's surface.  And lustre is the most important factor determining the quality of a pearl. It is especially important that the surface be without blemish because a smooth surface, without ridges deflecting the light, is naturally more lustrous. A pearl which is low in lustre is dim and monochromatic, but a higher grade of pearl with thicker nacre produces a resilient pearl with far fewer surface blemishes.  This creates a sharp, high-contrast surface that is almost mirror-like in its reflective qualities. The jewellery industry grades the lustre of pearls into five categories – "very high", "high", "medium", "low", and "very low". 

Size

The size of the oyster directly affects the size of the pearl it creates. Larger mollusks, for instance, create larger pearls. However, large cultured pearls require a larger nucleus to be implanted into the oyster, which increases the chance of the mollusk either rejecting the nucleus, or dying before a pearl has an opportunity to develop. A large nucleus also affects the complexion of the pearl.  It's more likely that a larger, mature pearl will be formed with greater surface defects. Round pearls are measured according to their diameter, while baroque pearls are measured by their length and width.  Size is determined by diameter and expressed in millimeters, since pearls are sold by the millimeter.

Pearls, of course, come in a range of sizes, these being the average:

Akoya:	6 to 8 millimetres in diameter, with 8 mm considered large.
Freshwater:	5 to 6.5 millimeters, for the best quality.
South Sea:	11 and 13 millimeters, large by any pearl standard.
Tahitian:	The match of the South Sea pearl, also between 11 and 12 millimeters.

Pearl strands are sorted by size, with a specific diameter range:

Petite:	6 millimeters and below.
Classic:	6 to 7.5 millimeters.
Most Popular:	7 to 7.5 millimeters.
Outstanding:	8 millimeters.

A pearl's size doesn't necessarily indicate its quality, but it most certainly does affect its price. Other things remaining same, the larger the pearl is, the higher its value will be.

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