Freshwater Pearls from China
China was one of the first to master the art of culturing. The Middle Kingdom began producing cultured pearls in the fourteenth century. In the 1960s a state-controlled industry introduced freshwater cultured pearls to the world market. Originally cultured using the wild Cristaria plicata or cockscomb mussel, initial production was of low quality baroque pearls, disparagingly known as rice crispies.
In the early 1980s, Chinese farmers abandoned the cockscomb in favor of the thicker shelled Hyriopsis cumingii or “three-cornered shell” mussel. Implantations of this new mollusk resulted in a breathtakingly superior freshwater pearl. By the early 1990s these pearls began to appear in force on the world market. Pearl culturing in China had come of age.
These new Chinese pearls are filling a niche hitherto occupied by Japanese Biwa pearls. Ironically, just as demand for fine freshwater pearls has increased, and the term “Biwa pearl” has come to connote the very finest in freshwater pearls, actual production at Lake Biwa has declined to the point of nonexistence. Pollution is the culprit! Industrialization surrounding Lake Biwa has sounded the death knell for Japanese freshwater pearls.
The Chinese are producing two types of freshwater pearls: tissue nucleated and bead nucleated. Tissue nucleation uses only a thin segment of living tissue from a donor mollusk to stimulate the development of the pearl.Bead nucleation is a relatively newer technique in China. Pearls of this type have been available only for about five years.
Tissue-nucleated pearls, which are by far the largest group produced, are mainly baroque pearls and are available in many bizarre and amazing shapes. Bead nucleation, as of this writing, has produced round pearls as large as fourteen millimeters.
Chinese pearls come in a variety of hues including pink, apricot (yellowish orange), peach (pinkish orange), champagne (slightly pinkish yellow), plum (reddish violet), bronze (reddish brown), and every shade in between. Unlike black pearls, these pearls can be bleached white by prolonged exposure to the sun or by soaking the pearl in a bleaching agent for several hours. Natural color Chinese freshwater pearls should be stored in a darkened environment in order to preserve the natural pastel color, since they may fade with long exposure to sunlight. Color in pearls is not a part of the quality equation. Apricot is not more beautiful than champagne. That is a question of preference and simpatico.
Orient and Overtone
Chinese pearls appear to have relatively opaque nacre. In smooth, relatively round pearls, the orient will exhibit itself as a slight darkening of the body color, plus perhaps a bit of pink.
Orient can best be judged if the pearl is viewed against a color that is close in hue and therefore neutralizes the body color of the pearl. Diffused daylight is the best viewing environment. In this lighting the overtone is seen in the actual reflection of the light source; the other color seen is the body color. Incandescent light can sometimes produce the opposite effect, bleaching out the color toward the center of the round pearl. In such cases, the orient may be found in the surrounding halo.
|Chinese freshwater pearl strands of exceptional luster and orient; the orient color surrounds the
body color on each individual pearl like a halo.
The Rainbow Effect
Baroque China pearls tend to exhibit a rainbow effect, a quality unique to this type of pearl. This is particularly true of the more baroque tissue-nucleated variety. The more texture, the more pronounced is this effect. Rainbow iridescence must be distinguished from true orient. Though beautiful and desirable, it appears to be a surface effect, not the result of refraction. Rainbow iridescence is probably caused by light reflecting in different directions off the pearl’s surface. This phenomenon is called interference; light rays literally bump into one another, resulting in the breakup of white light into various spectral colors.
Symmetry is the least important factor in evaluating a pearl. A majority of Chinese pearls are baroque, occurring in many strange and fanciful shapes. Baroque pearls, like fine abstract sculpture, may assume shapes that in no way detract from (and in fact contribute to) the beauty of the pearl. While it is true that curved surfaces bring out the beauty of the orient in a pearl, and that perfection of form does carry a substantial premium in the marketplace, the requirement that a pearl be perfectly round seems, at least to me, somewhat arbitrary.
Baroque pearls present the flexible aficionado with an opportunity to acquire a beautiful gem at a price which is dramatically less than the price a pearl with comparable luster, orient, etc. would bring in a pearl with perfect symmetry.