Through implementation of the project "Improving pearl processing technology and manipulation technology of jewelry from sea pearls (Pinctada martensii Dunker)" (code KC07.DA04/11-15), engineers of Vietnam Pearl JSC have successfully built the dyeing technology for yellow or “golden” pearls.

This technology is as follows: commercial pearls (pearls treated for cleaning) wil be used as the basis to calculate the quantity of dye solution; pearls are spread on the tray, then the tray is placed onto the stand of a dyeing barrel; dyeing process is conducted at 80 °C for 48 hours, the temperature up/down rate is 1oC/2 minutes, and the flow rate of dye solution is 0.05-0.1 m/s; the dyed pearls are repeatedly washed with neutral soap and water, then dried in a MS-T.2012-1 dryer at temperature of 38-40oC; the final step is sorting pearls and finishing products with Carnauba Wat. The dyed pearls have the rate of homogenous colour at 83%, rate of commercial finished products at 98-99%, relative hardness of 3-3.5 mohs, light fastness at 7-8, and friction fastness at 4-5.

For more information, please contact: Vietnam Pearl JSC

No.77, Alley 443, Nguyen Trai street, Thanh Xuan district, Hanoi

Source: http://vister.vn