The fewer and smaller the flaws are, the more valuable the pearl. Blemishes on single pearls tend to be more obvious and less acceptable than those on strand. It's normal for pearl strands to have some flaws. Natural pearls normally have more flaws than cultured Japanese Akoya pearls. That's because they've been in the oyster longer and have had more time to develop blemishes. Cultured pearls from the South Seas are also more likely to have flaws than Akoyas, which have a thinner nacre coating.
Grading Pearl Surface Quality
The smoothness and regularity of a pearl's surface helps determine its value. The closer a pearl's surface is to perfect, the more valuable it is. Ideally, a pearl's surface would be perfectly smooth and even, with no bumps or flaws. However, it's practically impossible to find a truly perfect pearl in nature. Every genuine pearl has at least a few flaws, like birthmarks, that grew as a part of the pearl.
The latest GIA Pearl description system defines four categories of surface quality:
1. Clean Pearls are blemish-free or contain minute surface characteristics.
2. Lightly blemished Pearls show minor surface irregularities.
3. Moderately blemished Pearls show noticeable surface characteristics
4. Heavily blemished Pearls show obvious surface irregularities.
In essence, pearl grades have no meaning except what the seller assigns to them. If examine the pearls yourself, use your own judgment and consider the following:
1. The prominence of the blemishes. Visible flaws away from drill holes are more serious than those near the holes. High bumps can be more noticeable than small pits or low bumps.
2. The type of flaws. Chipped or missing nacre is usually more serious than bumps even though it may be less noticeable.
3. The percentage of the pearl surface that is flawed. It's a lot more serious if 80 % of the surface of a pearl is flawed than if only 10% of it is. You need to roll the pearls to check this factor.
Blemishes are acceptable or not?
When judging a pearl's quality, a jeweler or savvy buyer will look at how visible or obvious the flaws are, and also whether they will damage the pearl over time.
1. Cracks throughout the pearl surface are the most serious flaws because they indicate structural weaknesses. Cracks will usually grow bigger and, over time, cause the pearl to break apart.
2. Patches or chunks of missing nacre affect both the beauty and durability of the pearl.
3. Prominent flaws like a large, visible bump on a single pearl would not be acceptable, but it would be okay in a strand. While buying, you may pay closer attention to an expensive pearl setting, one whose imperfections can be hidden.
4. Obvious discolorations throughout the pearls. For the sake of beauty, try to select pearls with a uniform color. There are plenty of them available.
5. Blemishes which cover the majority of the surface of the pearl. They can cause a viewer's attention to be directed more at the blemishes than at the pearls.
Wrinkles or bubbles in a pearl's surface are less serious flaws. These can be tiny, requiring a microscope or magnifying glass to see. Every genuine pearl will have a few of these; if a pearl is flawless even under magnification, it is definitely false.
The quality of a pearl's surface also affects its luster. The fewer flaws a pearl has, the more lustrous it will be which brings its value up significantly. A pearl should have a shiny, glowing surface. A chalky or dull surface indicates an inferior pearl. Keep in mind that it's normal for pearls to have a few flaws.
Certain flaws show up better against black or other dark colors background. Under a strong light, look at all sides of pearls under different types of lighting-bare/diffused, fluorescent/ incandescent, close/distant. Each type may bring out different details in the pearls.
Other Pearl Quality Factors