On the Surface

April 1998

For Your Staff:Selling Pearls

On the Surface

When the oyster yields a smooth, blemish-free pearl, it's a triumph of nature and one mark of high quality

by Devin Macnow Executive Director Cultured Pearl Information Center

Think of good-quality pearls and you'll likely think of smooth surfaces. In fact, surface is the second most important aspect in evaluating a cultured pearl after luster.

Surface quality refers specifically to the abundance or absence of physical blemishes or flaws. When evaluating surface (the trade uses such terms as blemish, spotting and cleanliness), remember that cultured pearls are grown by live oysters in nature. As such, there are many uncontrollable forces that affect the surface.

Environmental conditions combined with the relative health and genetic perfection of the host oyster, for example, play key roles in determining the perfection of a pearl's surface. In fact, fewer than 1% of all cultured pearls have surfaces that are perfectly smooth or completely free of surface flaws. Even the highest-quality cultured pearls may have a little spotting or blemishing. Naturally, the fewer the blemishes, the more valuable the pearl.

Two Types of Flaws
The most common flaws or blemishes are divided into two categories: damaging and non-damaging.

Non-damaging flaws don't affect lifespan or durability. They do affect aesthetic beauty, appearing as bumps, pits, welts or wrinkles. They're caused by excess or irregular nacre buildup on the core nuclei of a cultured pearl during the long growing process.

In the case of non-damaging blemishes, it's their relative abundance or absence that determines the pearl's quality and price. In some instances where blemishes occupy over 25% of the surface, the value can drop by half.

And just because a pearl may seem to be blemish-free now doesn't guarantee it was never flawed. Quite often jewelry manufacturers select a blemished area to drill the hole necessary for future stringing and setting. This isn't a deceptive procedure; it's merely a practical way to eliminate a blemish while making the pearl ready for jewelry finishing.

The Question of Durability
Damaging flaws such as chips, cracks and pinholes not only detract from the overall beauty of a pearl, but also may influence durability. They also tend to become larger over time and cause the nacre to peel or chip, damaging the pearl and lowering its value.

Drilling can create cracks and chips near the drill hole if the technician makes an error in his calculation. Or perhaps the nacre was brittle and cracked under the severe heat and pressure of drilling.

Other damaging flaws may be caused by irregular nacre formation. These include pinholes, which penetrate deep into the layers of nacre and may expose the core nuclei. These also tend to enlarge through regular wear and can become clogged with dirt.

It's important to note that virtually all pearls have some spots or blemishes, so examine them carefully to determine their severity and their capacity to affect the pearl's lifespan. If non-damaging flaws can't be seen by the naked eye from a distance of two feet, for example, they're likely not serious and won't detract from the pearl's overall beauty. In fact, pearls with high luster often can mask small surface flaws.

Though the surface is an important basis to evaluate quality, there is one exception: low-quality pearls are often smooth and free of visible surface imperfections simply because there's not enough nacre to create a blemish.

Here are examples of a range of cultured pearl surface quality. The pearl at left has a damaging pinhole. Beside it is a pearl with a damaging chip and crack. Next are non-damaging bumps and pits, then non-damaging wrinkles and finally a blemish-free pearl.

Copyright © 1998 by Bond Communications.


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