Freshwater cultured pearls originate from freshwater
mussels in freshwater sources. Rivers, lakes and streams
are the home of freshwater pearl mussels. Freshwater
mollusks produce pearls, which can compete marine mollusks
in color and luster. Another point to be noted here is
that certain species of freshwater mollusks can produce
multiple numbers of pearls at a time. They are produced by
China, Japan and the United States. A very popular type of
freshwater cultured pearl is the Biwa pearl. Biwa pearl
used to come from the mussels grown in lake Biwa of Japan.
Lake Biwa is the largest freshwater lake of Japan. However
because of rising pollution in this lake, the production
of pearls have stopped. Freshwater shell and pearl mussels
are from the family Unionidae. About 20 different species
are commercially harvested from this species. A mother
shell produces tons of freshwater pearls. The most common
color among freshwater pearls is white. Mussels type,
determines the color of the pearls. Pink pearls usually
originate from big washboard mussels (Megalonaias
nervosa). Threeridge mussels (Amblema plicata) have pearls
in shades of lavender and blue-green. Muckets (Actinonaias
ligamentina) produce fine pink pearls, and sand mussel (Lasmigona
costata) has salmon-pink pearls. Other mussels used to
produce freshwater pearls are heelsplitter, butterfly,
pimple back, ebony, pistol grip, mapleleaf, three-ridge
pigtoe, and elephant ear.
In the early 19th century, the button industry cherishing
in the Midwest relied for their pearl consumption on North
American pearl mussels. They needed thick good size
pearls, which North America hosted. For hundreds and even
thousands of years, the freshwater pearls of Asia, Europe
and North America are being priced. In the last 50 years
more than 35 species of eastern North America have gone
extinct because of pollution and loss of habitat.
Conservation efforts are into force for protecting the
remaining species. Presently freshwater mussel shells meet
the material requirements of bead nuclei, which pearl
farmers around the world implant in marine pearl oysters
to create cultured pearls. Many North American mussels
produce good quality pearls. These pearls are used since
2000 years in the production of decorative objects and
jewelry. American freshwater pearls were unpopular till
mid 18th century, but as people discovered spectacular
pearls in rivers and streams around the United States they
became popular. The beginning of large-scale pearl
production started, first for the pearls and afterwards
for the mother-of-pearls that were used for making
buttons. During the major span of 18th century people
mostly harvested freshwater pearls. However a change
occurred in 1887 when a German button maker, John
Frederick Boepple, came to United States and settled in
the Mississippi River town of Muscatine, Iowa. He
established a mother-of-pearl button factory in 1891. This
factory received its raw material, the thick-shelled
American pearl mussels, from nearby rivers and streams.
Gradually with the passage of time this small town, Iowa,
came to be popularly known as “Pearl Button Capital of the
World”. This factory spread its operations in Europe,
where the shells of Indo-Pacific marine mollusks were used
for button making. Due to the abundance of pearl mussels
and cheap local labor freshwater pearl industry in the
United States cherished at the end of 19th century. Button
makers in Muscatine, Iowa, produced 1.5 billion buttons in
1905, which was almost 40 percent of the buttons produced
in the world. Further in 1916 US factories based in Iowa,
New York and New Jersey, produced six billion buttons
priced at $12.5 million. 9700 mussel fishers and 9500
factory workers were employed in this industry.
Another major change occurred to the button industry by
the emergence of plastic industry. Around the idle of 20th
century most of the Mucatine’s button makers lost their
business. This forced mussel fishers of the Midwest to
search for a new market and they started sending their
shells to foreign factories. With the decline of
Midwestern pearl button industry due to plastic buttons, a
new market for pearl mussel shells began to emerge. Around
1920s, Japanese pearl cultivators started importing
hundreds of tons of pearl mussel shells each year. They
used these shells to cut and put into nuclei of marine
pearl oysters. Shell material being identical to nacre is
quite suitable for this purpose because of its whiteness.
So by 1960s exports of pearl mussel shells became a major
export for states near and around the Mississippi river.
This region exported around 7000 tons of shells in the
year 1993 and gradually has become the major source of
nuclei for use in pearl cultivation in all parts of the
world.
