Cultured pearls of freshwater or river. 1-. What is a cultured pearl? A cultured pearl is a Pearl whose formation process is identical to that of the natural Pearl. The secretion of the layers of nacre is due to metabolism of molluscs, but with the difference that the beginning of their training process is caused by the intervention of man and its development is carried out in a controlled environment. We can distinguish between cultured pearls in molluscs from salt water and pearls cultured in freshwater molluscs within cultivated pearls. The main difference between the cultured saltwater pearls and cultured freshwater pearls is that the vast majority of these are not nucleated by synthetic core, if not organic epithelia of another mollusk is implanted. 2-.
How are pearls of freshwater or river grown? The freshwater mollusks are nucleated by making a small incision in the epithelium of a mollusc from 6 to 12 months of age and inserting (grafting) a square section of epithelium between 3 and 4 mm in another mollusk. The most common practice is to perform around aged between 12 and 16 deployments by leaflet, giving us a total production of 24-32 pearls. After implantation the molluscs are returned to the water where they remain between 2 and 6 years. A perlifero SAC with a Pearl is formed by each implementation. The result are formed entirely of nacre pearls, given that implanted epithelium section dissolves within the perlifero SAC, but not having a hard core which guide the process of growth the pearls are rarely perfectly round. Sometimes after 1 or 2 years, that the pearls have a size approximately 6 – 8 mm, are separated from the mollusc, are coated with another epithelium and return to enter in the same or another mollusk to improve his form.
Cultivation periods ranging from 3 to 8 years. Freshwater molluscs used mainly for its production are Hyriopsis Schlegelii Hyriopsis Cumingii. Also the use of hybrid molluscs has proliferated in recent years. Pearl production cultured water sweet spreads to China, United States and Japan. These pearls now account for 95% of the marketed quantity. 3-. Why is more competitive and has grown so much the production and market of cultured freshwater pearls? Among the main reasons we have:-producing molluscs mortality rate is noticeably lower than the of molluscs from salt water, and can be used up to three times. -The size of the freshwater molluscs is significantly higher than the salt water which allows a greater number of implantations – the price/quality ratio. 4-. Main treatments applied to freshwater pearls:-dyeing. Silver nitrate or any other organic compound is used to darken the Pearl nacre. The chemical compound penetrates the layers of nacre and produces a chemical reaction with light and sulfate hydrogen producing a powerful black color. Other organic or inorganic dyes can be used to obtain other colors beads. -Irradiation. The use of gamma rays for darken the nucleus of the Pearl. This process creates colors with tendency to the polychrome, passing by gray and violet black. The appearance of the irradiated freshwater pearls has an intense metallic shine. -Gloss. Pearls are heated and cooled or treated with products to coat the surface of the Pearl artificially improving their presence. Leather Bracelets and Pearl cultured original author and source of the article