The Cultured Pearl The Buying Guide

Getting to know Gems

How to select, buy, and care for, and enjoy Pearl Jewelry

The difference quality makes

Quality: Key to lasting beauty

More important than knowing what type of pearl you have is knowing whether or not you have a good pearl, and how to tell the difference. Just as there are differences in quality that affect the beauty, desirability and cost of diamonds and colored gemstones, there are differences in quality that affect the beauty, desirability, and cost of pearls.

The same factors are judged when evaluating natural and cultured pearls, but different standards are used to arrive at the overall quality classification, that is, “poor,” “good,” “fine,” and so on. Here we will limit our discussion of quality to the evaluation of cultured pearls. To develop an appreciation for quality differences in natural pearls, we suggest taking advantage of any opportunity you have to see and compare natural pearls to develop your own eye for differences in each factor. This can be done by viewing natural pearls in museum collections, at auction viewing, in antique jewelry exhibitions, and so on. Your jeweler may also be able to locate natural pearls for you to review. As you compare them, keep in mind the factors described in this article, noting the range in variations. It won’t be long before you are able to distinguish unusually fine natural pearls from those that are fair or poor quality.

Pearl Quality is the #1 consideration in selecting cultured pearls

Understanding quality differences in cultured pearls is perhaps even more than for diamonds and colored gems because quality differences can affect how long the beauty of pearls will last. A fine pearl is gem that will stand the test of time, a thing of lasting beauty to be enjoyed and cherished from generation to generation; a poor quality pearl can quickly lose its beauty, in some cases after only months!

Finding the perfect balance within a pearl for lasting beauty

Each pearl producer must decide how to best balance all the factors involved so that a lovely pearl is produced, at an affordable price, without unnecessary risk. It is truly a game of chance. The longer the pearl remains in the oyster, the greater the potential loss in the event of disease, natural disaster, or other calamity. In terms of quality, more time means thicker nacre and, potentially, a more lustrous, longer lasting pearl. But the longer the pearl is in the oyster, the greater the extent to which other desirable characteristics; shape, color, and surface perfection, may be adversely affected. As mentioned before, for example, since the nucleus starts out round; and since nacre doesn’t crystallize uniformly around the entire nucleus, at the same time, it may become increasingly out-of-round as nacre builds up around it, and the surface may become blemished.

Pearl producers must constantly weigh potential benefits against risks, but there is no standard guideline. Some producers take greater risks than others in an effort to produce the rarest and most beautiful pearls, allowing the pearl to remain in the oyster for the longest possible time; these are the costliest cultured pearls. Others try to minimize every risk, often by shortening the cultivation period.

Today, the cultivation period among many producers has been reduced from 18 months to less than one year, with average running at about eight months. Although improvements in nutrition and overall care have resulted in improved quality and better nacre production by the oyster, most industry experts agree this is too short a period to produce pearls with nacre thick enough to assure lasting beauty; thin nacre cost much less, but they have no longevity and there are questions as to whether they should be purchased at any price. Many pearls are now sold with nacre so thin they won’t last any time at all; others have somewhat thicker nacre, and look better, but still won’t stand the test of time. For this reason, nacre thickness may be the most important factor to consider when selecting pearls. Fortunately, this is a difference you can often see with your eye!

Differences in pearls that can be seen with the eye

An unusual characteristic of pearls not found in most other gems is that quality differences can usually be seen with one’s own eye! The ability to see differences comes fairly quickly once you understand what to look for as you consider various pearls, and how to examine them; you’ll be surprised how quickly you will start to notice differences and become more selective.

First using the eye alone; this is all one usually need. In some cases, it may also be helpful to use the jeweler’s loupe.

How to use a loupe

To check drilled pearls more closely, or to examine surface blemishes, it also may be helpful to use a loupe, a special type of magnifier used by jewelers. It should be a 10-power, triplet type; a triplet has been corrected for distortion and color fringing, in a black housing (not chrome or gold plated).

With a few minutes practice you can easily learn to use the loupe to examine pearls. Here is how:

1. Hold the loupe between the thumb and forefinger of one hand.
2. Hold the pearl or strand similarly in the other hand.
3. Bring both hands together so that the fleshy parts just below the thumbs are pushed together and braced by the lower portion of each hand just above the wrists.
4. Align the loupe with what you are examining so that the item is about one inch away from the loupe.
5. Now move the hands/loupe/pearl; keeping them all braced together, up to your nose or cheek, bringing the loupe as close as possible; if you you wear eyeglasses, you d not have to remove them.
6. Get a steady hand. It’s important to have steady hands for careful examination. With you hands still together and braced against some part of your face, put your elbows on a table or countertop. (If table is not available, brace your arms against your chest or rib cage.) If you do this properly, you will have a steady hand.

Practice with the loupe, keeping it approximately one inch (more or less) from the ey, and about an inch from the pearl. Learn to see through it clearly. It is difficult to focus initially, but with a little practice it will become easy. You can practice focusing on any object that is difficult to see; the pores in your skin or a strand of hair.

Play with the item being examined. Rotate it slowly, tilt it back and forth while rotating it, look at it from different angles and different directions. It will not take long before you are able to focus easily on anything you wish to examine. If you are not sure about your technique, a knowledgeable jeweler will be happy to help you learn to use the loupe correctly.

What you will see with the loupe

With practice and experience, a loupe can tell even the amateur a great deal. You will not be able to see what a trained gemologist will see, but here are some ways it can be helpful for the beginner when examining pearls:

1. To check the drill hole to better estimate the size of the hole; to check for line of demarcation between nucleus and nacre (indicating cultured pearl rather than natural pearl); and to spot traces of dye (traces of dye may be seen just inside the drill hole).
2. To examine surface blemishes more carefully, to spot cracks and missing nacre that would indicate poor nacre quality or nacre that is too thin.
3. To see surface characteristics that might indicate imitation since the surface of cultured (and natural) pearls look very different from imitations; once you have observed the surface of a pearl you know is cultured pearl, and compare it with one you know to imitation, it’s easy to spot imitation pearls.

How to examine pearls to see quality differences

Before beginning, it is very important to understand there is no internationally accepted grading system for pearls. Pearl dealers and jewelry retailers use their own systems. These systems often use the same alphabetical nomenclature; we often see pearls graded “Triple A” (AAA), “Double A” (AA), “A”, “B”, or “C”; but since they aren’t based on the same standards or criteria, they don’t necessarily reflect comparable qualities. With no standardized criteria, the quality represented by one seller may be much higher, or lower, than that of another; one jeweler’s “Triple A” quality may be the equivalent of another’s “C” grade.

You can not assume that you are comparing comparable pearls based on terms such as “AAA”, “AA”, and so on. With pearls, you must learn how; and what, to examine.

1. View pearls against a neutral background.

When examining pearls, view them against a neutral, non-glossy background. A very light gray is ideal, or a flat white white background (such as white tissue paper, always available in jewelry stores). Never view pearls against only a black background; pearls look very beautiful worn against black, but black makes if difficult to see subtle, costly differences.

2. View pearls in cool white fluorescent or light light.

Avoid intense spots lights or incandescent light (luster will always appear more intense under strong direct light such as sunlight or spot lights; it will always look lower in diffused light, as on a cloudy day, or under fluorescent lights). Keep in mind that the type of light in which you examine pearls will affect what you see, so pearls being considered should be viewed and compared in the same light. When possible, compare them in the same place, at at the same time of day. (Pearls can look different from one geographic location to another for the same reason; differences in light from hemisphere to hemisphere).

3. View pearls at a right angle to your body.

When comparing strands of pearls, as in necklaces or bracelets, lay them on the neutral background at a right angle to your body so that the strands are close to one another but not touching. This will make it easier to see differences, especially in color and luster.

The six factors that affect pearl quality and value

Now that you know how to view pearls to make quality comparisons, let’s talk about what to examine. Regardless of the type of pearl, or whether it is natural pearl or cultured pearl, the following factors must be evaluated to determine whether or not it is a fine pearl that will give you lasting beauty:

- Luster and orient
- Nacre thickness and quality
- Color
- Surface perfection
- Shape
- Size

Nacre thickness, and the quality of the nacre, have a greater effect on the beauty of a pearl than any other factor; and with a cultured pearl, on how long it will last. For this reason, it is considered the most important factor. However, “luster” and “orient” will first be discussed because this is what people notice first; what makes the pearl special, and because differences in luster and orient provide visual clues to nacre thickness.

The combination of the lovely reflective glow we call luster and the soft iridescent play of color we call orient is what distinguishes the pearl from all other gems. They are also the most easily seen indicators of a pearl’s quality, and of its potential for lasting beauty.

Luster

When you see a fine pearl, the first thing you notice is its lustrous glow. Luster is not a superficial “shine” such as you see in imitation pearls, but an intense brightness that results from rays of light traveling through the numerous layers of nacre and being reflected back form within the pearl. One might describe it as a “shine with depth.” In a pearl with good luster, there will be a sharp contrast between the pearl’s brightness area (the part in direct light) and the shaded area; sometimes the contrast creates the illusion of a “ball” within the pearl; the more intense the image of the ball, the better the luster. Luster is evaluated on the sharpness of brightness of the reflection, which depends upon the quality and the quantity of light reflected from its surface. This, in turn, depends upon the quality and thickness of the nacre produced by the mollusc. The thicker the nacre (and the smaller and more transparent the microscopic crystals comprising it), the better the luster. When numerous layers of nacre have crystallized properly and each layer is well aligned with the other, the result is an exquisite, intensely lustrous pearl.

How to judge luster

Anyone buying pearls should take time to learn evaluate luster and, in particular, to recognize what is acceptable and what is not acceptable; in particular, when luster is too low. Low luster not only reduces the beauty of the pearl, but can provide an indicator of very thin nacre. With Japanese pearls, low “chalky” luster usually indicates a very thin nacre coating that can quickly crack, peel, or simply wear off, leaving just mother-of-pearl beads. (Imitation pearls will give longer pleasure than poor quality, chalky cultured pearls, and usually at a lower cost!).

Rule 1: Look for pearls with high luster. Luster is judged from very high to very low. A pearl with very high luster will seem vibrant, and the light reflection (the intensity of the “ball”) will be sharp and bright; a pearl with very low luster is dull, and the reflection hazy, chalky or nonexistent. To judge luster:

- Roll the pearls to view them from all sides to make sure the luster is uniform.
- Examine them under a light source such as a fluorescent lamp, looking for reflections of the light off the surface, paying particular attention to the brightness or sharpness of the reflections. Avoid strong, direct light. If the available light is too strong, hold your hand over the pearls to shade them, and examine in the shadowed area.

Top quality Japanese Akoya cultured pearls can have a higher luster than other white round cultured pearls because of the water temperature in which they are produced. Cold water causes slower nacre production, which normally results in superior crystallization and overall nacre quality. When the nacre quality is good, and it is exceptionally thick, Japanese Akoya pearls can have incredible lustrousness. The luster can also be very chalky, indicating very thin nacre, or poor quality nacre.

Iridescent orient

When the nacre is well formed, and very thick, you will observe orient, a soft, iridescent play-of-color across the pearl’s surface. This iridescent quality is only present when the layers of nacre are thick enough to cause a prismatic effect (white light divided into all the colors of the rainbow) as the light travels through them.

When the nacre is well formed, and very thick, you will observe orient, a soft, iridescent play-of-color across the pearl’s surface. This iridescent quality is only present when the layers of nacre are thick enough to cause a prismatic effect (white light divided into all the colors of the rainbow) as the light travels through them.

Round cultured pearls that exhibit this iridescent orient are highly prized and sought by connoisseurs. Today, it is rare to find round cultured pearls that possess this sublime characteristic, but it can frequently be seen in the irregular shapes of baroque pearls, adding to their allure. For orient to be present, each layer of nacre must be well crystallized and aligned, and, most important, the nacre must be unusually thick. This is why orient is often seen in fine natural pearls; which are all nacre, and in fine, older strands of Japanese cultured pearls, which have thicker nacre than those normally being produced today. An iridescent orient can also be seen in the irregular shapes of baroque pearls, where the shape causes depressions in which the nacre collects in deep “pools,” and in pearls with very long cultivation periods, such as South Sea pearls, American freshwater cultured pearls, and fine quality, all nacre Chines “potato” pearls.

Luster and orient are important not only because they affect the pearl’s beauty, but as we continue to stress, because they are a visible indicator of nacre thickness and quality.

Nacre thickness and quality

Whether natural or cultured pearl, the thickness of the pearl’s nacre and its quality is what gives the pearl its unique beauty. The thicker the nacre and the better the nacre quality, the more lustrous and iridescent; the more exquisite, the pearl.

Nacre thickness determines the pearl’s longevity; the thicker the nacre, the longer the life of the pearl; the thinner the nacre, the shorter the life. Finding the right balance to get an adequate nacre thickness without jeopardizing other factors such as shape and surface perfection takes skill and experience, as mentioned earlier. The farmers producing the finest, most beautiful cultured pearls are those who allow the nucleus to remain in the oyster the longest possible time between the implanting and harvesting, to obtain the thickest possible nacre coating.

Nacre quality determines how the light travels through the layers. Sometimes pearls with thick nacre fail to exhibit the intensity of luster or orient that is expected. This normally results from the particular way in which the layers of nacre crystallized. For reasons nobody fully understand, the nacre crystals have not formed with a good transparency, the layers are not uniform, or they are not properly aligned. It is not known the rate at which nacre is produced affects its quality. If nacre is produced too fast, it will be less transparent. The result is a pearl with lower luster; light enters the pearl, but less is reflected back. This is not necessarily bad. One must always weigh the important of one factor against another. A thick nacre South Sea pearl with subdued luster will be more affordable than one with higher luster; it can still have a lovely character and, costing less, might enable you to acquire a larger size.

There seems to be a connection between nacre quality, water temperature and stability of overall water conditions. Pearl producing oysters in the warmer waters of Australia, Tahiti, the Cook Islands, Philippines, and Indonesia produce nacre much faster than the Japanese or Chinese; some experts estimate production to be fifteen to twenty times faster. This means that even if the pearls is left in the oyster for the same amount of time as Japanese pearls; and fine South Sea pearls usually have a longer cultivation period, the nacre would be much thicker. Fine South Sea cultured pearls often exhibit an iridescent orient because of their thicker nacre. As said before, this is rare today in white Japanese pearls, but fine Japanese pearls usually exhibit a much brighter, sharper luster attributed to the colder waters. Japanese pearls that exhibit both intense lustrousness for which they are known and a soft, iridescent orient indicating thick nacre are very rare. Such pearls, however, are among the most beautiful and prized of all.

To have a lustrous, iridescent pearl, the nacre quality must be good and the nacre layers must be thick; it is a combination of the two that affects the quantity and quality of light reflected back from the surface. While there may be pearls with thick nacre that don’t exhibit rich luster and orient because of how the layers crystallized, there are no pearls with rich luster and orient that do not have fine, thick nacre. Any pearl that exhibits a rich lustrousness is one that has thick nacre; and, since nacre must be thick to produce the iridescent effect we call orient, any pearl which shows this lovely iridescence must have thick nacre.

How to judge nacre thickness

In natural pearls, the pearl is entirely nacre; in saltwater cultured pearls, it can range from very thin to very thick, averaging about 10% - 15% of the total pearl diameter, and rarely exceeding 30%. Nacre thickness of South sea cultured pearls much greater any other cultured pearls and the finest may be 40% - 50% nacre.

When nacre is too thin, pearls will not last. With pearls commanding the price they do; then, no one would knowingly buy pearls that won’t last. So here are some ways to estimate nacre thickness, and avoid pearls with thin nacre:

- Look for orient.

If the pearl has a uniform iridescence playing across its surface, it has very thick nacre. Don’t worry about any pearl that display a lovely orient.

- Note the intensity of luster.

Pearls with a bright, intense luster that sharply reflects nearby images, will have a good nacre thickness; pearls that look very dull or chalky probably have very thin nacre or poor quality nacre.

- Check for cracks and peeling.

Pearls with very thin nacre crack easily, often revealing the nucleus. Also, thin nacre will peel or wear off over time. In some cases, the nacre is so thin that new pearls have already begun to peel, leaving small areas of exposed mother-of-pearl. Check carefully for any exposed mother-of-pearl.

- View the pearl near the drill hole with a loupe.

Shine a very bright light, the brighter the better, a few inches over the hole. Examine the hole, noting where the nacre ends and the mother-of-pearl begins; the nacre is always lighter. Mentally estimate thickness.

- Check for banding.

When viewing pearls with a strong light as described above, check to see whether you can see any alternating lighter and darker areas or bands; if so, you are seeing the “layers” of the mother-of-pearl nucleus, and this indicates a thinner nacre than is ideal.

Grading nacre thickness in Japanese pearl strands:

- Very think - At least 0.5 mm on all pearls
- Thick - At least 0.5 mm on most pearls
- Medium - Between 0.35 mm and 0.5 mm on most pearls
- Thin - Between 0.25 mm and 0.35 mm on most pearls
- Very Thin - 0.25 mm or less on most pearls

In cases where you can’t be sure of nacre thickness, it is strongly recommended to submit pearls to a gem testing laboratory for a report indicating nacre thickness.

Color: Silvery white to blackest night, and a rainbow in between

Color is an important factor to consider for several reasons. Individuals have very personal references in terms of color based on their own skin, eye, and hair color and should select a color that is best suited to themselves. Color also affects cost because some are rarer than others. Perhaps most important, there are more colors of cultured pearls being produced today than ever before, offering unusual and distinctive alternatives to traditional white pearls, and additional pearl choices for any occasion.

How to evaluate color

For white cultured pearls, there are two principal elements involved in evaluating color: body color and overtone. Some also include “orient” in the evaluation of color, and when it is present, it certainly affects the overall impression of the color seen. The “body color” refers to the basic color, i. e., white cream, yellow. The “overtone” refers to the presence of a secondary color (its “tint”), usually a pinkish, greenish, silver or blue tint. When we speak of color in pearls, we are referring to the combination of the body color and overtone. White-rose would mean white pearls with a rose colored overtone (tint); naturally white pearls with a blush of pink are rare and expensive. Creamier pearls are less rare and more affordable. In white pearls, the rarest and costliest overtone is “pink” (rose); a green overtone is considered less desirable in white pearls, and its presence reduce value.

In pearls that have a “fancy color” or hue; a distinctive color clearly distinct from the “white” / “off-white” category, there is an additional color element: tone. This refers to color intensity, and is graded from “light” to “dark.” A dark yellow pearl, for example, will have a much richer color than a light yellow pearl; it is also much rarer, more desirable, and costlier.

In naturally “black” cultured pearls, the color can range from light gray to black, and also includes blue and green; overtones are usually green or pink (rose). In black pearls, a green overtone is the most rarest and most costly, especially when it results in an intense “peacock” color. A pink overtone in gray or black pearls creates mauve or “eggplant” colors These are less rare and costly, but still lovely and distinctive.

Cultured pearls are available in many colors; white, gray, black, pink, green, blue, gold, from many parts of the world. The Philippines are known for yellow and golden pearls; Tahiti, other islands of French Polynesia, and the Cook Islands for naturally black cultured pearls. Untreated, natural color Chinese round freshwater cultured strands consisting of many colors all strung together, called harlequin pearls are also highly sought.

Fancy color pearls can be very rare and, depending upon the color that interests you, difficult to find. Anyone searching for a fancy color should take time to visit several very fine jewelers (and search also online jewelers) to see the full range of colors available. This will help you select a color with which you will always be pleased.

Techniques to artificially enhance color

While pearls occur in a range of colors naturally, sometimes the colors are induced by artificial techniques. Today most white Japanese cultured pearls have been bleached to make them whiter, then dyed ti impart tints. White pearls that have been dyed after being drilled for jewelry use (as in a pearl necklace) can usually be detected easily by a qualified gemologist. By examining with a loupe at the drill hole, you may even be able to detect the color enhancement yourself. If the peals is dyed, and if you can see the line of demarcation between the nucleus and the nacre, there will be a visible concentration of pink or reddish dye in the conchoilin layer (which is spongy and absorbs the dye).

For unusual colors, especially the costly black variety, it is recommended to send pearls to a gem testing lab with sophisticated equipment to know for sure whether or not the color is natural.

There are no standard systems for describing or communicating color, so once again it is up to you to look at pearls carefully, developing your own eye to see differences in the body color, overtone and tone.

Pearl surface perfection

Think of the pearl’s surface as you would your own skin. Just as our own is rarely completely free of little imperfections, so it is with the pearl. Surface perfection refers to the pearl’s “skin” being free of such things as small blisters, pimples, spots, or cracks. Imperfections may also appear as dark spots, small indentations, welts or blisters, or surface bumps. While occasional small blemishes are not uncommon, if large or numerous they are unsightly. A pearl with sizable or numerous blemishes may also be less durable. The cleaner the skin, the rarer and costlier. If drilled, the closer the blemish to the drill hole, the less it detracts from both appearance and value.

Sometimes dark spots results from contact with perfumes, oils, cosmetics, and so on. If superficial, they can sometimes be removed by rubbing a mild polishing compound gently across the surface with a chamois cloth.

How to judge surface perfection

- Examine in several types of light.

While diffused light is normally best for comparing quality factors in pearls, when checking for blemishes, an intense light may highlight certain types. When examining pearls for blemishes, it may be helpful to check them with with diffused light and an intense bright light.

- Examine against a dark background.

A light background is normally best for comparing most pearls characteristics, but when checking for blemishes, it is sometimes easier to spot them against a dark background.

- Examine while rolling.

Place the pearl or pearl strand on a flat surface and roll it to be sure you have examined all sides, and so that the light catches any blemish and highlights it.

- Hold the pearl up.

Hold the pearl up and examine them while holding out in front of you, at eye level.

Practically speaking, there is no such thing as a “flawless” pearl; they are exceptionally rare. In strands, this is even truer. One must decide what is important to you in terms of color, shape, size, and so on, and then balance the factors accordingly. I recommend sacrificing the surface perfection somewhat rather other factors. Selecting pearls that are slightly blemished may enable one to purchase pearls with thicker nacre, a more desirable color, or larger size. Also keep in mind that if the pearl has intense luster, most blemishes won’t even be noticed; high luster helps conceal them! A dull chalky white pearl, however will show every blemish, no matter how small.

Avoid pearls with cracks. Cracks can be serious and may lead to peeling nacre, especially if the nacre is thin.

Pearl Shape

Shape in pearls is divided into three categories: spherical, symmetrical, and baroque. The rarest and most valuable is the spherical or round pearl; these are judged on their degree of “sphericity” or roundness. While fine pearls that are perfectly round are extremely rare, closer a pearl comes to being perfectly round, the more expensive it will be. Pearls with shapes such as the teardrop or pear shape are symmetrical pearls, and are judged on proportioning, outline, and good symmetry; that is, whether they have a nice, pleasing, well-balanced shape. Symmetrical pearls are usually less expensive than round pearls; although there are some exceptions, but much more expensive than baroque pearls, which are irregularly shaped pearls.

Any strand of pearls should be well matched for shape, and when worn give the appearance of uniformity.

New shapes are being produced today that do not really fall into any of the three categories above. These include “coin” pearls, which look like flat coins; thin, rectangular “bars”; “potato” pearls, which resemble an oval potato; and “ringed” or “circle” pearls, which exhibit concentric rings from top to bottom.

Terms such as semi-round and semi-baroque are also used. These are terms applied to pearls that are “out of round” but not so much that the irregular shape is interesting, or distinctive. These cost much less than other shapes.