Pearls
with a nucleus
The
species that is used is called Hyriopsis Schlegeli and is cultured in Lake
Biwa (Japan), therefore the pearls originating from this species are also
called Biwa-Pearls.
A round nucleus (8 - 10 mm), made of shell is implanted into the
oyster (near the gonad). The growth-rate of the nacre is about 2
mms per year, the harvest takes place after 2 or 3 years. The pearls are
most often baroque ore have the shape of a tear-drops, perfectly round
pearls are very seldom, the colour varies from white to gray and bronze. |
Pearls
without a nucleus
The
species that are used are Hyriopsis Schlegeli and Cristaria Plicata and
both are cultured in Lake Biwa (Japan) and in Chinese Rivers.  In
the place of a round nucleus, small pieces of epithelial tissue of
other pearl-oysters are implanted near the lateral area. Due to this fact
it is possible to breed 10 pearls on each side.
 The
growth-rate of the nacre is about 0.7 - 1.5 mms per year and after 3 years
the pearls are ready to be harvested. At this time the pearls have a size
of 3 - 7 mms and a bronze, white, gray or pink colour, their shape is round,
boroque or flat. |
