Study On The Microstructure, Elementary Composition And Black-dyeing Optimized Of Inferior Southern Pearls

Cultured pearls in Liu Shawan, Zhanjiang have famous reputation of “ China’s southern pearls come out of Liu Shawan ” from ancient times because the natural geographic and environmental advantages. Cultured pearls in Liu Shawan are famous for their perfectly round, bright and smooth, shining clean, exquisite and elegant, fresh and lovely luster and superb luster, which symbolize generous, holy, rich, happy and macrobiotic. For the past few years, without the implementation of scientific planning breeding, cage culture, scallop culture, and shrimp culture have inundated other than pearl culture, which leads to deterioration of ecology and environment, field aging, so as frequent disease. The output of pearls is from 40 tons in 2005, shrunk to less than 1 ton now, and the quality is declining. The qualified pearls(Fig.3-1) accounted for about 30%,and inferior pearls(Fig.3-1) accounted for as high as 70%. Pearl breeding has been confronted with dire challenges for the government and researchers of pearls.Inferior pearls is defined as the surface defects of defective farming pearls and impertinent bleached pearls such as fogged-pearls, desquamated-pearls or spotted-pearls,which are gone out of use because of under mustard.In this work, inferior seawater cultured pearls in Liu Shawan, Zhanjiang are as the research object. In order to understand the cause of inferior pearls, explore the microstructure of pearls, rich mineralization principles, so as provide basic information of aquatic water, the microstructure and elementary composition were tested; For the sake of improving its value and increasing the income of the pearl, black-dyeing technology was explored.In this work, The organic layer on the surface of the nuclear、the prismatic layer and the nacreous layer were observed by SEM; The main composition of organinc layer was explored by FTIR. Elements of internal surface, layers and powder of pearls of high-quality and poor-quality pearls cultured pearls in Liu Shawan were measured by X-ray Probe Spectrometers(XPS), Field-Emission Scanning Electron Microscope X-Energy Dispersive Spectrometer(FESEM-X-EDS) and Inductively Coupled Plasma Mass Spectrometry(ICP-MS) in order to understand the cause of poor-quality pearls may be achieved; With the rate of attained pearls and dyeing results as indexes, and the black-dyeing temperature, Ag+:NH3,so as to black-dyeing time,the research on inorganic black-dyeing technology of pearls in Liu Shawan was burrowed by single factorexperiment and orthogonal experiment. The results as follows:1. Study on the microcosmic structure of cultured seawater pearl in Liu ShawanThe organic matter was confirmed to exist with uneven size of spherical and irregular globular, fiber filaments with porous. There is a “transition-like layer” with the thickness of 1.73μm between the prismatic layer and the nacreous layer. Aragonite crystal was confirmed by FTIR in the organic layer on the surface of the nuclear. The profile of the pearl was corroded by EDTA, where the fibrous and porous network was found between the aragonite tablets of calcium removed pearls, and the aragonite crystals grow by the organic pore, which provided new evidence for the mineral bridge. The organic matter corroded by EDTA in the nacreous layer was different from that in the prismatic layer.2. The Compare Study on Elements of Seawater Cultured Pearls in Liu ShawanIn the internal surface of pearls, organic protein content in variegated layer of poor-quality pearls was more than that of high-quality pearls; Under the SEM, variegated layer existed in poor-quality pearls, which contained more N and S than prismatic layer and nacre layer; In pearls, prismatic layer and nacre layer mainly contained C, O, N, Ca,with the atom percent of 99%; The contents of Mg, Zn, Fe, Mn in high quality pearl are less than that in poor quality pearl.3. The research on inorganic black-dyeing technology of pearls in Liu ShawanThe research on black-dyeing technology of pearls in Liu Shawan was burrowed by single factor experiment and orthogonal experiment. The results as follows: the black-dyeing temperature was 50℃, the Ag+:NH3 was 1:3 and the black-dyeing time was4 d.