The full article shared by Kari Anderson, which discusses the process and sale of these 'Pearls'...
Buddha Blister Pearls
The following information is from a 1908 publication.
They used several forms of matrices or nuclei, but principally spheres of nacre and bits of flat metal or molded lead, which were not infrequently in conventional outline of Buddha. In the spring or early summer, these were introduced under the mantle of the living mollusk after the shell had been carefully opened a fraction of an inch, and the animal was then returned to the pond, or lake. The mollusk did its work making Chinese pearls in a leisurely way, like some people who have little to do, and many months elapsed before it was ready for opening and the removal of the Chinese pearly objects.
The most satisfactory description we have seen of this process appears to be that communicated nearly a century later to the London Society of Arts by Dr. D. T. Macgowan, through H. B. M. plenipotentiary in China, from which this account is abridged and modified.
The industy is prosecuted in two villages near the city of Titsin, in the northern part of the province of Che-kiang, a silk-producing region. In May or June large specimens of the fresh-water mussels, Dipsas plicatus, are brought in baskets from Lake Tai-hu, about thirty miles distant. For recuperation from the journey, they are immersed in fresh water for a few days in bamboo cages, and are then ready to receive the matrices.
These nuclei are of various forms and materials, the most common being spherical beads of nacre, pellets of mud moistened with juice of camphor seeds, and especially think leaden images, generally of Buddha in the usual sitting posture. In introducing these objects, the shell is gently opened with a spatula of bamboo or of pearl shell, and the mantle of the mollusk is carefully separated from one surface of the shell with a metal probe.
The foreign bodies are then successively introduced at the point of a bifurcated bamboo stick, and placed, commonly in two parallel rows, upon the inner surface of the shell; a sufficient number having been placed on one valve, the operation is repeated on the other. As soon as released, the animal closed its shell, thus keeping the matrices in place. The mussels are then deposited one by one in canals or streams, or in ponds connected therewith, five or six inches apart, and where the depth is from two to five feet under water.
If taken up within a few days and examined, the nuclei will be found attached to the shell by a membranous secreation; later this appears to be impregnated with calcareous matter, and finally layers of nacre are deposited around each nucleus, the process being analagous to the formation of calculary concretions in animals of higher development. A ridge generally extends from one pearly turmor to another, connecting them all together. Each month several tubs of night soil are thrown into the reservoir for the nourishment of the animals. Great care is taken to keep goat excretia from the wter, as it is highly detrimental to the mussels, preventing the secretion of good nacre or even killing them if the quantity be sufficient. Persons inexperienced in teh management lose ten or fifteen percent by deaths; othes lose virtually none in a whole season.
In November, the mussels are removed from the water and opened, and the Chinese pearly masses are detached by means of a knife. If the matrix be of nacre, this is not removed; but the earthen and the metallic matrices are cut away, melted resin or white sealing-wax poured into the cavity, and the orifice covered with a piece of shell. These Chinese pearly formations have some of the luster and beauty of true pearls, and are furnished at a rate so cheap as to be procurable by almost anyone. Most of them are purchased by jewelers, who set them in various personal ornaments, and especially in decorations for the hair. Those formed in the image of Buddha are used largely for amulets as well as for ornaments. They are about half and inch They are about half and inch long, and while in the shell have a blueish tint, which disappers with removal of the matrix. Quantites of them are sold as talismans to pilgrims at the Buddhist shrines about Pooto and Hang-chau.
In some shells the culture Chinese pearls are permitted to remain by the Chinese pearl growers, for sale as curios or souvenirs; specimens of these have found their way into many public and private colections of Europe and America. These shells are generally about seven inches long and four or five inches broad, and contain a double or triple row of pearls or images, as many as twenty-five of he former and sixteen of the latter to each valve. That the animal should survive the introduction of so any irritation bodies, and in such a brief period secrete a covering of nacre over them all, is certainly a striking physiological fact. Indeed, some naturalists have expressed strong doubts as to its possibility, supposing the forms were made to adhere to the shell by some composition; but the examination of living specimens in different stages of growth, with both valves studded with them, has fully demonstrated its truth.
It is represented that in the northern part of the Che-kiang province about five thousand families are employed in this work of growing Chinese pearls in connection with rice-growing and silk-culture. To some of them it is the chief source of income, single families realizing as much as 300 silver dollars annually therefrom. In the village of Chung-kwan-o, the headquarters for cultured Chinese pearls, a temple has been erected to the memory of the originator of this industry, Yu Shun Ynag, who lived late in the thirteenth century, and was an ancestor of many persons now employed thereby.
