Three Japanese men are credited with the simultaneous invention of the cultured pearl in the last decade of the 19th Century. They are Mise, Nishikawa and Mikimoto. Kokichi Mikimoto developed the process of mass-producing cultured pearls through ocean farming, and is therefore properly credited with the formation of the cultured pearl industry.
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, working to convince them they had even greater beauty than the natural pearl strands which had been the staple of their businesses for many decades. 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.
• 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.
• Tahitian cultured pearls: larger pearls, usually gray to black, but 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.
• 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.
Quality Characteristics of Cultured Pearls
There are no universally recognized grading scales to help jewelers and the public communicate the quality characteristics of cultured pearls. The complex and subtle nature of shape, color, surface features, nacre thickness, luster and polish has hindered the search for grading language that can be both accurate and repeated with consistency when used by trained gemologists and pearl buyers. However, three expert pearl buyers in 3 parts of the globe will observe and discuss characteristics of quality and reach very similar conclusions about value, without the requirement of uniform language or scales. Here is a list of quality characteristics, which, along with the size of the pearl, determine the cost of the necklace.
Nacre (Thickness) and Luster:
This is the most important determinant of cost of a cultured pearl necklace. Thicker nacre will be produced if the nucleus is left inside the mollusk for longer periods of time. This results in higher luster and 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 of nacre, which is still sufficient to produce wonderful pearls.
Unfortunately, the great majority of necklaces are produced from much shorter growing periods, leaving on average about .3mm nacre, with substantial quantities of necklaces showing only .1mm to .2mm. This produces average to poor luster, and coupled with the use of hair spray, perfume and other cosmetics, may wear through the thin layers of nacre in just a few years, leaving only a faintly covered nucleus.
Shape:
The best pearls are round, and when all pearls on a necklace form perfect circles, the cost increases. When some pearls become even slightly out-of-round, the price drops. Button pearls are used to make beautiful earrings. Baroque pearls are heavily misshapen beads and are always much less expensive, with the exception of the best quality South Sea baroque strands, which may be expensive because of size, color and luster.
Body color and overtone color:
Body color is viewed when the necklace is placed against white paper, under white light, and the pearls turned by hand. Body colors include white, cream or silver, among others. The overtone color can be seen in the circle on the surface of the pearl. Overtone colors include rose, celadon and gray. When all pearls on a necklace match in both body and overtone colors, the cost rises. Because pearl color is often enhanced with bleach, dyes and or irradiation, it is important to talk with your jeweler about the origin of color in the necklace, so that you can evaluate the affect of the treatment on cost.
Surface condition:
Most pearls have surface features called pittings, blemishes or roiling, among others. As with imperfections in diamond, the number of blemishes, their location on the surface and how they affect luster are all part of the cost of the strand. Particularly damaging are tiny holes that appear in the nacre, and continue to the nucleus. Such pearls are inexpensive, even with strong nacre and high luster.
Polish:
After pearls are removed from the mollusk and treated for color, they are polished before they are strung. Heavier nacre allows for stronger polish, which adds to the reflective capacity of the bead. When all pearls on a strand receive the same degree of polish, the value of the necklace increases.
Buyer Beware! Pearls with short growth periods and poor nacre can still be nicely polished, and appear to be lustrous. Pearl buyers can distinguish between luster created by thick nacre and nicely polished pearls with minimal nacre. Matching: The best cultured pearl necklaces consist of pearls which match one another in each and all of the quality characteristics. As pearls vary up and down the strand in these characteristics, the cost drops quickly.
