Lightweight Coin Pearls: detailed description
More massive than pearls produced in a second harvest, lightweight coin pearls are cultivated by inserting pieces of plastic sheeting together with large grafts of mantle tissue in a first operation. The broken pearl in the photo grew around a textured bit of plastic like imitation leather.
The size and weight of many examples indicate that they have been in mussels for several years. The downside of very large size pearls in the mantle is that the chances of the pearl being joined to the shell are increased. A majority of the largest pearls produced with flexible nuclei, and as a second harvest following them, stick to the shell. Pearls’ value is sharply reduced by gaps in their surface nacre wherever they have to be cut from the shell, and jewelry makers strive to hide such cuts.
Unlike shell nuclei (bead and coin) thin bits of plastic contribute little to the weight of the pearl. This might be a reason that so many vendors call these lightweight-coin pearls non-nucleated. The average price per weight of coin pearls is lower than that of non-nucleated second-harvest pearls, partly because coin pearl nuclei represent a considerable part of the weight of the pearl produced, and a pearl without nucleus is all nacre. Since the relationship between the weight of cheaper inserted material and of the pearls harvested is probably more similar to non-nucleated pearls than coin pearls, the wish to classify the product with the former group is at least understandable. Many cultivators of coin pearls appear to have switched to producing lightweight coins because the market for coin pearls had fallen below production costs during the recent glut.
Nucleation is generally done using shell, and no shell is used in lightweight coins. Another factor that helps deter disclosure about nucleation with bits of plastic is that the use of materials other than shell as nuclei is frowned upon in general. The reason is that the usability of the pearls may be adversely affected. Materials with significantly different expansion coefficients may produce pearls that will spontaneously crack as a result of temperature changes, and difficulties in drilling holes are common. We have not done much drilling of lightweight coin pearls, but the problems appear to be less severe than those we have experienced with other non-shell nucleus materials such as antimony coins or wax beads. There tend to be irregular spaces and sharp edges along the drill holes, however, that may be an obstacle to speedy restringing in some cases.
A similar technique using celluloid flat nuclei was experimentally used in Japan to make “dragon” pearls, which are flat and very large, often with several non-nucleated pearls adhered to one face. A problem encountered with celluloid nuclei is that drilling into them may generate enough heat to cause discoloration of the pearl. Given a strong prejudice throughout the pearl establishment against nucleation with any material other than shell, examples from Japan are very scarce.
Like them or not, lightweight coin pearls are a significant part of China freshwater pearl production, apparently replacing much of the slower and therefore higher-cost production of non-nucleated second-harvest pearls of large sizes. Pacific Pearls offers lightweight coin pearls and mixed strands incorporating them in a variety of shapes and sizes. We are eager to disclose what we have learned about all the types of pearls we sell, because this allows customers to make informed choices, and to avoid making inaccurate claims.
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