What are blister pearls? Picture it: China. Year 1290. A small sect of Buddhist monks has made a name for itself by producing little, lustrous amulets in the figure of the Buddha. These personal ornaments were just as popular among the young and fashionable, as among the old and devout. The rich luster across an undulating surface ensured a constant interplay of light and interest. The properties seemed divine. But how did man produce such wondrous charms? By turning to one of man and nature’s oldest friends: the mollusk.
The Chinese (in particular, history credits a man called Yu Shun Yang) had discovered that by inserting beads, mud pellets, or tiny figurines beneath the mantle tissue of freshwater mussels, they could in time harvest pieces far more lovely and lustrous. The mussels had done what mussels do when faced with an intruder: sooth the irritation by wrapping it in layers of smooth, alleviating nacre. When this happens within the mantle tissue of a mollusk, like an oyster or mussel, pearls are formed. When this happens between the mantle tissue and the shell, whether naturally in the wild or man-induced, blister pearls are formed.
Blister pearls form commonly in nature when a parasite bores or drills into a mollusk’s shell. Man simulates this by gently prying open the shell and lifting the mantle tissue, and then sliding a dome-shaped mold between these two parts. These curios or souvenirs need not come only in the form of the Buddha or a dome, but could be any fairly thin, flattened form. The mollusk then begins to secrete layer-after-layer of nacre over the invader, forming within six months or more the prized blister pearl. When the mollusk is first opened, blister pearls appear as bumps or bubbles along the shell lining. They may be left in situ or intricately cut out and liberated. Through this same process, and after much trial and error, man began to perfect the art of culturing wholly round, freestanding pearls at the beginning of the twentieth century – producing the pearls most often found in jewelry today.
The culture and sale of whole pearls far exceeds that of blister pearls in the modern marketplace, but some jewelers still find unique ways of incorporating blister pearls into jewelry and ornaments. Cristaria plicata, the native Chinese pearl-producing mussel favored by Yu Shun Yang’s crew, is no longer the only species used to culture blister pearls. Abalone blister pearls are particularly popular, as the culturing process for blister pearls is rejected far less than whole round pearls are in abalone. This is because abalones have a type of hemophilia that, when cut, causes the mollusk to bleed to death. They also are big movers, commonly dislodging any attempt at implanted nuclei. Because of this, the centuries-old art of culturing blister pearls remains current in our modern age.