How to raise/culture fresh water pearls?

Question

How to raise/culture fresh water pearls?

Answer 1

http://www.pbs.org/wgbh/nova/pearl/fresh...

Answer 2

put a seed piece of shell inside fresh water oysters

Answer 3

A detailed answer to your question would take about 1000 pages but I can touch on the basics.

Currently freshwater pearls are nearly exclusively farmed in China in the Hyriopsis cumingii and Hyriosis schlegelii freshwater mussels. Cristaria plicata has also been used in China, and a hybrid of H.c. and H.s. is used on a small scale in Lake Kasumigaura in Japan.

Freshwater cultured pearls, unlike saltwater cultured pearls, do not require a bead nucleus. They are created by a method of grafting utilizing only a small piece of tissue (mantle tissue) from a donor mussel.

The donor tissue is selected and cut into small 3 mm squares. A 6 month-old host mussel is coaxed open and held open with small piece of wood. The grafting technician then makes 12 - 16 small incisions in the lower valve of the host mantle. In each incision is placed a small piece of donor tissue. It is twisted upon insertion to increase the probability of a round pearl. After each incision has received a graft, the shell is turned over and the procedure is repeated on the opposite valve. The piece of wood is removed and the mussel constricts.

After the operation the shells are returned to a freshwater environment where they are tended for a period of two to five years. Upon harvest each shell will produce between 24 and 36 pearls. The shell may be returned to the water after harvesting the pearls as the remaining pearl sacs will continue to produce nacre and a "keshi" petal pearl will develop.

After harvest the pearls are cleaned, sorted for size and shape, and then processed. The processing includes a type of "maeshori" (pretreatment), a bleaching treatment, a heat treatment, and a chemical luster treatment. The pearls are then drilled, polished, and matched on temporary strands known as hanks. At this point they are ready for wholesale.