Pearl is one of the most beautiful and most popular gems throughout history. Despite the huge surge in diamond popularity in the 20th century, the necklace of Japanese Akoya cultured pearls remains the single most requested piece of jewelry worldwide. It is also one of the most complex. Necklaces of large, top quality South Sea cultured pearls sell for hundreds of thousands of dollars, while strands of fashionable Chinese freshwater cultured pearls are available from $20 to $500, allowing all customers the world over to enjoy this fabulous gem.
Unlike diamond and most colored gemstones, EVERY FEATURE OF PEARL CAN BE SEEN WITH THE NAKED EYE. What is beautiful about the pearl is visible. What is not fine is also visible. NOTHING IS HIDDEN. Therefore, this is the gem where you should purchase as fine a quality as your budget allows, concentrating on nacre thickness and luster first, followed by other quality characteristics.
NATURAL, CULTURED & IMITATION PEARLS
A natural pearl is formed when a grain of foreign matter floating in the ocean works its way into the mantle tissue of a bi-valve mollusk. The mollusk secretes layers of nacre around the foreign body, in order to protect the delicate tissue. This forms a natural pearl.
A cultured pearl is the result when a pearl farmer inserts a tiny piece of mother-of-pearl (nacre from a Mississippi River mollusk) into one of several species of mollusks, and the mollusk secretes nacre to protect itself. Imitation pearls are manufactured in laboratories/factories generally out of glass or plastic and coated with a chemical that enhances the luster of the beads and creates a gritty surface like that on cultured and natural pearls.
The most famous brand of imitation pearl is the Majorca, manufactured in Spain. To state the obvious, all pearls used in jewelry before culturing was invented are natural, unless replaced in jewelry with cultured pearls over the generations. Natural pearls form in oceans, rivers and lakes all over the globe. The most important source continues to be the Persian Gulf, in the nations of Bahrain and Oman. Natural pearls from this area are called “oriental pearls” by jewelers and gemologists.
Gemologists and jewelers who are experienced buyers of both natural and cultured pearls can often identify each by eye, usually based on a combination of shape, color and luster. However, the only proof positive way to do this is by x-ray and other laboratory tools. Quality for quality and size for size, necklaces of natural pearls are more expensive than those composed of cultured pearls. Therefore, jewelers selling such necklaces provide laboratory documents for accurate identification of origin.
Necklaces of natural pearls are uncommon in the retail marketplace, and are generally sold by stores that specialize in estate and antique jewelry or come to market through the auction process. Small natural pearls are still available for use in the add-a-pearl necklaces so popular in the 1950’s and 60’s, and as replacement pearls in antique jewelry.
By the late 1920’s and 1930’s, retail jewelers around the world were introducing necklaces of these well-matched rounded beads to their clients, representing them as having greater beauty than the natural pearl strands which had been the staple of their businesses for centuries. The public caught on, and demand for cultured pearl necklaces and pearl jewelry increased and has remained strong ever since.
Categories of Cultured Pearls (A Partial List):
- Classic Japanese Akoya cultured pearls represent the core of the industry. Fine quality examples of these pearls are also cultured by several companies in Tennessee. Chinese pearl farmers also use the Akoya mollusk but have not yet mastered the production of fine quality necklaces to match those from Japan.
- Lake Biwa Japan freshwater cultured pearls: generally small beads of different shapes and colors sold primarily in fashion jewelry pieces.
- South Sea cultured pearls: larger pearls of different shapes and colors from Myanmar, Indonesia, Australia and the Philippines. Generally speaking, pearls from Myanmar and Australia are white or silver white while pearls from Indonesia and the Philippines are golden.
- Tahitian cultured pearls: medium size to larger pearls, with gray to black body color, sometimes with beautiful rose and celadon overtone colors.
- Chinese freshwater cultured pearls: The best of these pearls are almost round, but they lack the combination of luster and color that is so important to the beauty of the classic Japanese pearl necklaces from the akoya mollusk. China has been tremendously successful in their production of freshwater cultured pearls of different shapes, and most of these necklaces are very inexpensive.
- Blister “mabe” cultured pearls: these are “half” pearls cultured on the lid of the mollusk which are typically used to make large and fairly inexpensive earrings, rings and necklaces.
JUDGING PEARL QUALITY
Judging pearl quality is complicated and requires years of patient and continuous practice. Quality features apply to a single pearl, pearls on a necklace as well as pearls in all kinds of jewelry.
NACRE THICKNESS FROM LONGER GROWING PERIODS
The thickness of nacre surrounding the center nucleus is the most important determinant of cost of a cultured pearl necklace. Thicker nacre will be produced if the nucleus is left longer inside the mollusk. More layers of nacre produce brighter and richer luster and therefore more beautiful pearls. Luster is defined as the quantity and quality of light that refracts from the layers of nacre and combines with the reflection of light from the surface of the polished pearl. Before World War II, it was not uncommon for pearls to be left growing from 4 to 6 years, producing almost 1mm of nacre around the nucleus, resulting in gorgeous luster. Modern techniques allow farmers to reduce the growth period to 2 years, and the finest quality necklaces today exhibit about .6mm to occasionally .8mm of nacre, which is still more than sufficient to produce wonderful pearls.
Nacre thickness is impossible to measure but can be determined by X-ray. Expert pearl buyers can determine the growth period (and therefore estimate nacre thickness) just by eyeing the luster, and can also easily distinguish the difference between the glow from heavy nacre and the glow from reflected light from surface polish.
Sadly, most pearls are removed and brought to market more quickly. These have less nacre and less luster. Modern polishing techniques have improved surface reflection of light, so when the necklace is new, the pearls still look pretty. This is NOT refracted light from thick nacre. It is merely reflected light from surface polish, and it does not last. Within a few years, many of the pearls become lifeless. It happens gradually, and the process is hastened by the use of perfume and hair spray.
Pearls are cultured in many shapes, by simply inserting nuclei with different shapes. Generally pearls are placed into 3 categories for shape: round, symmetrical and baroque. The best pearls are round, and when all pearls on a necklace form perfect circles, the cost increases significantly. Symmetrical pearls would include oval, button and drop. These are not considered baroque meaning misshapen pearls; rather they are considered fancy shapes, very much like fancy shape diamonds (diamonds other than the round brilliant). Pearls from different parts of the world are classified by different shapes. The dark Tahitian cultured pearls are subdivided into 5 shapes: round, drop, button, baroque and circled. A baroque cultured pearl is misshapen. An out-of-round pearl is just slightly misshapen, but not nearly enough to be labeled baroque.
The most diverse selection of shapes comes from the huge annual production of Chinese freshwater cultured pearls. Almost all these necklaces are inexpensive fashion. However China has continued its experiments with the Japanese Akoya mollusk in hopes of some day producing round pearls with the same color and luster as their Japanese counterparts. As of 2016, China is coming close as there are a few strands now and then with very round pearls, but not yet with the same color and luster.
BODY COLOR AND OVERTONE COLOR (Iridescence)
Gemologists look at the body color of the pearl, which is the color everyone sees. Japanese akoya cultured pearls have 3 body colors: rose, white and cream. We identify that color. We identify how even or uneven it displays fully around the pearl. We identify its intensity and vividness. We then look at what is called Overtone Color(s). Overtone color is iridescence, one of the “light phenomena” of the gem kingdom. An iridescent color is a SECONDARY color appearing to float in a circle above the body color of the pearl. Japanese pearls show pink, blue and green iridescent colors. The rarest and highest quality would be a combination of pink and blue, creating a purple overtone color floating above a white pearl.
Pearls from Lake Biwa Japan grow with many fancy colors. In the 1990’s, strong pink and orange pearls from Lake Kasumingaura reached western markets under the name Kasuminga. These pearls were seldom round and exhibited wrinkles and knots along their surfaces. Black, brown and reddish black pearls from Japan are dyed, and we now know that most of the gray and black Tahitian cultured pearls are treated to deepen or make their natural color more even. Certain mussels used to culture freshwater pearls in China produce intense mauve, orange, purple and pink colors in addition to white. These fancy colored pearls may be stabilized by a bleaching process before they are strung into necklaces.
BLEACHING, DYEING AND COATING
Like most colored gemstones, most pearls are enhanced in some fashion after they are removed from the mollusk. The question of what kind of treatment is ok and what kind is deceptive continues to be debated within the industry. I believe that all treatments to improve the quality of a pearl should be disclosed to the buyer. Most pearls are bleached and then polished. Bleaching is known to create a uniform color. After bleaching, most Japanese Akoya pearls are then colored to produce light pink overtone. Such pearls are not considered dyed, and the pearl industry has accepted this process for decades, without the need to disclose it to the buyer. Dark pearls from Japan are created by immersing them in a silver nitrate solution. Certain large pearls from Tahiti showing a dark color are also treated in this fashion.
Blue, green, purple and brown aniline dyes are also used to color cultured pearls. Gemologists can sometimes test these pearls for dye by using ultraviolet fluorescence and or by microscopic examination of the drill hole, and there are additional tests available at advanced gemological laboratories.
A difficult challenge is determining the origin of golden color in South Sea cultured pearls. Chemically dyed pearls are substantially less expensive than natural golden South Sea pearls. The GIA is currently researching a reliable test for these pearls even though the pearl industry admits that the great majority of golden pearls are dyed in some fashion.
Some Akoya cultured pearls and some white and black South Sea and Tahitian pearls are coated with a type of silicon polymer film to improve luster. There are several methods of testing for this type of enhancement.
Few pearls have unblemished surfaces. Gemologists consider the size, distribution, type and visibility of surface markings. Like imperfections in diamonds and inclusions in colored gemstones, pearls grow with many kinds of surface marks. These include bumps, roiled skin, knots, grooves, pits, dull spots, scaly spots, growth rings and many more. If the surface markings are immediately visible, the pearl is downgraded and much less expensive. If the beads must be examined closely to see blemishes, we would call these slight growth characteristics and they would not degrade the value of the necklace very much. Many Chinese freshwater pearls show wrinkling on their surfaces. They are often compared to raisins or prunes.
Especially damaging on any type of pearl are tiny holes that appear in the nacre and continue to the nucleus. Such pearls are inexpensive, even with strong nacre and high luster.
Every pearl on a necklace is polished once it is removed from the mollusk. How carefully and evenly this is accomplished is part of pearl quality analysis. As stated earlier, even pearls created with very short growth periods, with minimal nacre, can be nicely polished, though the polish will fade over the years as there is no nacre to support it underneath.MATCHING
The best cultured pearl necklaces consist of pearls which match one another in each and all of the quality characteristics and size. With any of the quality features, if they are inconsistent up and down the strand, the cost drops quickly. If almost all pearls in a necklace are round and only a few are slightly out-of-round, the cost is downgraded only slightly. Matching applies to the very finest Japanese akoya cultured pearls, the finest South Sea cultured pearls and the most inexpensive cultured pearls, regardless of where they are grown. No more than 25% of the value of a pearl necklace can be attributed to matching.
PEARL SIZE AND LENGTH OF NECKLACE
Pearls on a necklace should vary by no more than one half millimeter; therefore a necklace may contain pearls that range from 7.5mm to 8mm, as long as both sizes are represented on the strand. If the pearls vary by more than one half millimeter, the cost drops. An exception would be a necklace of purposefully graduated cultured pearls, often provided as wedding gifts decades ago. Graduated necklaces are beautiful and go in and out of fashion over the years.
As with other gemstones, as size increases, price increases, all other factors being equal. Consumers should always ask to try on at least two sizes, adjacent to one another. Example: 6.5mm to 7mm and 7mm to 7.5mm. The larger pearls create a more expensive necklace, and for some buyers, the half millimeter difference may not be worth the extra money.
Lower quality pearls have smaller price increases as they increase in size. Finer quality pearls have greater price increases as they increase in size. This is because the longer the nucleus is left in the mollusk, the greater the risk of the destruction of the pearl from disease, ocean upheavals and other factors in the under water environment. Perfectly round pearls with multiple years of growth, beautiful color and relatively blemish free skin are very expensive simply because there are very very few necklaces available with those characteristics. Too many things can happen under water and in some years, a majority of the pearl crop is damaged and unsalable when harvested.
The pearl industry generally divides necklaces into 3 lengths; short necklaces called choker, necklaces about 24 inches called matinee and long necklaces termed opera. At various times, fashion dictates length. Over the 20th and into the 21st century, the 18 inch choker remains the most popular necklace.
PEARL CARE & STRINGING
Each time, when pearl jewelry is removed, the pearls should be wiped gently with a soft pearl cloth, as this removes the chemicals and body oils from everyday wear. Cultured pearls with strong nacre that are cleaned and re-strung regularly will retain their luster and beauty for generations.
PEARL BRANDS & THE MIKIMOTO NAME
Mikimoto farms produce all qualities of cultured pearls, from the heaviest nacre, most gorgeous necklaces of Japanese Akoya beads, Tahitian black pearls and South Sea cultured pearls to very common commercial quality strands and pierced earrings sold by many of their retail accounts. Because of their marketing, many clients ask for Mikimoto pearls, not really knowing why, but presuming they are fine quality.
Many jewelers sell generic cultured pearl jewelry, some of which is just as fine as the top grades from Mikimoto. Depending on the harvest and the availability of fine quality necklaces, generally Mikimoto pearls are substantially more expensive that duplicate size and quality non-branded generic pearls.
Despite this, Mikimoto continues to represent high quality pearls and very fine pearl designed jewelry in the international jewelry industry. In addition, not every city has jewelers who are experts in pearl quality analysis and who buy for their stores the same higher quality strands sold by Mikimoto.
Like all gemstones, quality differences in pearl necklaces of the same size create significant ranges of cost. Here are some examples using the most popular Japanese Akoya cultured pearl:
6mm to 6.5mm, 18 inches — $300 to $3500.
6.5mm to 7mm, 18 inches — $400 to $4000.
7mm to 7.5mm, 18 inches — $500 to $5000.
7.5mm to 8mm, 18 inches — $600 to $6500.
8mm to 8.5mm, 18 inches — $700 to $8000.
8.5mm to 9mm, 18 inches — $800 to $12,000.
9mm to 9.5mm, 18 inches — $1000 to $16,000.
14k white gold friction back stud pierced earrings
6mm to 6.5mm — $30 to $120.
6.5mm to 7mm — $45 to $140.
7mm to 7.5mm — $60 to $220.
7.5mm to 8mm — $80 to $320.
8mm to 8.5mm — $100 to $560.
8.5mm to 9mm — $120 to $1480.
9mm to 9.5mm — $150 to $2400.