what are freshwater pearls?
Freshwater pearls are produced by the Hyriopsis cumingi also known as the Triangle shell and the Hyriopsis schlegeli or the Biwa shell. These shells are grown in freshwater bodies of water like riverbeds, lakes, creeks, and ponds. Although some freshwater pearls are produced in USA and Japan, they are predominantly produced in China. Freshwater pearls are often small and an irregular shape. This is due to the process of which they are cultured.
The Origin of Freshwater Pearls
Freshwater pearls are produced by the Hyriopsis cumingi also known as the Triangle shell and the Hyriopsis schlegeli or the Biwa shell. These shells are grown in freshwater bodies of water like riverbeds, lakes, creeks, and ponds. Although some freshwater pearls are produced in USA and Japan, they are predominantly produced in China. Freshwater pearls are often small and an irregular shape. This is due to the process of which they are cultured.
Like all types of cultured pearls, freshwater pearls are produced through the process of a technician introducing an irritant into the inner lining of the shell. This process activates the defence mechanism of the shell to secrete layers of nacre, and this layering process produces a pearl. Because the introduced irritant is only the mantle tissue of a donor shell, they have no “template” to be guided with and this often results in the more irregular shape of a freshwater pearl. This is unlike saltwater pearls which are cultivated with both a mantle tissue and a seed. This seed acts as the template for the saltwater shell to hopefully produce a rounder shaped pearl, but it takes a highly skilled technician and a bit of luck from mother of nature to produce a round saltwater pearl.
The Shapes and Colours of Freshwater Pearls
Characteristically, freshwater pearls often range in shape from very baroque, to near round. Although any type of near-round or round pearl is the most desired, only 2% of freshwater pearls are this shape. More commonly freshwater pearls are defined by the following shapes: potato-shaped pearls, stick pearls, rice-shaped pearls, button pearls, coin-shaped pearls and drop pearls.
Freshwater pearls are cultivated and harvested in a relatively short period of time, especially in comparison to saltwater pearls – only taking about 6 months to produce up to 30 pearls at a time. At freshwater pearl farms, each shell is introduced with 24-32 “irritants” or pieces of mantle tissue. This process results in the production of up to 30 pearls at harvest and a single shell can showcase an array of colours, sizes, shapes, and qualities of pearls. Saltwater pearl shell typically only grow one pearl at a time over a two year period, making them comparatively rarer and more valuable than freshwater pearls.
Although the colour of freshwater pearls can be produced through natural means and often do showcase a wide spectrum of colours, it is widely accepted to treat or brighten freshwater pearls to achieve a desired colour. Typically, freshwater pearls display pastel shades of pink, lavender, peach which are then enhanced through colour treatments and are at times bleached to be lighter and brighter. Some freshwater pearls are dyed dark or almost black to resemble Tahitian pearls.