Overview
Freshwater cultured pearls are one of the most common and popular types of pearl sold today. Their durability, beauty, and affordability make them a definite favourite.

Freshwater cultured pearls are primarily produced in China by the Hyriopsis Cumingi and the Hyriopsis Schlegeli molluscs. Other regions, including Japan and the United States, also culture Freshwater pearls but nowhere near the quantities of China; producing 1500+ tons annually.

Freshwater pearls are cultured through a process called grafting. Grafting uses a donor mussel where narrow strips of mantle tissue are removed and cut into tiny squares. These tiny bits of mantle are then inserted into small incisions on the upper and lower valves of the new host mussel. The maximum number of grafts tolerated by a mussel while still allowing production of a decent quality pearl is about 32, or 16 grafts per valve. Freshwater cultured pearls are generally harvested after 2 to 7 years of cultivation.

After harvest, the pearls are cleaned and sorted by size and shape. Then the pearls are processed. First, the pearls undergo a chemical wash called maeshori to further clean and disinfect the pearls, and sharpen the lustre. Second, the pearls are bleached to brighten and remove any surface stains on the nacre. However, if the pearl has a strong natural colour like pink or mauve, the pearl is not bleached. Third, the pearls are drilled and polished. Fourth, and finally, the pearls are matched into temporary strands.

Size
Freshwater cultured pearls typically range in size from 1.0mm - 14.0mm, however there are always exceptions that occur; some baroque Freshwater cultured pearls can occur in much larger freeform shapes.

Colour
Freshwater cultured pearls naturally occur as white, peach/pink, and lavender/mauve, with a large pallet of these hues that vary in tone. All other factors being equal, the more intense the colour the more valuable the pearl. Freshwater pearls found in other colours such as black, bright green, chocolate brown, red, blue, etc., have been colour treated and dyed; the only naturally occurring black pearls are Tahitians.

Shape
Freshwater cultured pearls are available in a wide variety of shapes; such as round, near-round, off-round, rice, stick, baroque, coin, button, and drop. All factors being equal, the more perfectly round a Freshwater pearl is, the more valuable it is.