摘要
近期广州珠宝批发市场上出现了一种纹理、质感与象牙极为相似的仿制品材料,为深入认识其材料属性及鉴定特征,以三个该类仿制品材料的圆形吊牌为测试样品,采用常规宝石学测试、刀刮/热针测试、显微观察、红外光谱测试等,将其与象牙以及猛犸牙、河马牙、植物象牙、骨制品、赛璐珞、胶制品等常见仿象牙材料作对比研究。常规测试表明,该类仿象牙材料的折射率约为1.48(点测)、相对密度约为1.22;小刀切刮出现完整卷片,热针扎刺产生凹陷针眼、无黏性的颗粒状粉渣;显微镜下观察,该类仿象牙材料的内、外部纹理特征一致,从中心辐射边缘方向上纹理呈现由粗疏、不规则向细密、规则的渐变过渡,中心部位为大波浪纹层,中间夹层为较粗疏同心水波纹层,最外层为细密同心水波纹层,纹理线宽窄变化、边界模糊,呈独立"Z"字形弯曲延伸,不同于象牙的勒兹纹、交叉菱形图案及整体同心层状结构;红外光谱测试显示,该类仿象牙材料的物质组成单一,未经镀膜处理,最强红外吸收峰位于2 920、1 728、1 278cm^(-1)处,为醇酸树脂。此类材料的主要鉴别特征:独特纹理具有粗细、疏密渐变过渡,层次分明,为不完整的同心水波纹结构;颜色、光泽、折射率、密度等亦可辅助鉴别。
A fantastic simulated products similar to ivory in appearance such as graining and texture have arised in Guangzhou jewelry wholesale market in recent years, bringing about new tasks for identification of ivory and related accessories. In this paper, three circular tags are used as test samples, and conventional physical property test, knife scratch, hot needle spine, microscopic observation of texture, infrared spectrum analysis have been studied. The author contrasts the differences in internal and external characteristics with the other imita-tions such as mammoth teeth, hippo teeth, nut ivory, animal bones, celluloid, plastic prod-ucts and the real ivory. The routine test results showed that the simulated material has the physical parameters of refractive index 1. 48（point measurement） , relative index 1. 22 , and it emerges complete roll sheets while being scratched, and comes into hollow pinprick, granu-lar powder residue, white colour while contacting with hot needle. Microscopic observationindicated that the grain lines arrange in a gradual transition by coarse, irregular to fine from the center to the edge on the circular samples’ surface. The central is the rows of big wavy lines, and the middle layer is a rough concentric ripple, and the outer layer is fine concentric ripples. Each graining line changes from narrow to wide in width, and its boundaries are vague, extending in the curving and independent Z-shaped way. Furthermore, the texture and structure characteristics inside the simulated products are completely consistent with the outside, and lack of Retzius layers, cross-rhomb patterns and overall concentric structure of ivory. Infrared spectrometry indicated that the stimulated products has uniform material composition, without being coating. The main three strong infrared absorption peaks located at 2 920、1 728,1 278 cm^-1. None of vibration absorption spectrum peak is related to collagen amide linkage and PO4^3-,and drasticly differs from ivory. In brief, this stimulated material is a kind of macromolecule alkyd resin. Compared with the previous imitations, this stimula-ted material is characterized with its unique texture such as gradual transition of thickness and density, clear hierarchy and incomplete concentric ripple layered structure. Further-more ,colour, luster, density and refractive index can be used as an auxiliary basis for identi-fication.
出处
《宝石和宝石学杂志》
CAS
2017年第3期24-34,共11页
Journal of Gems & Gemmology
关键词
仿象牙材料
纹理特征
红外光谱
ivory imitation material
texture characteristic
infrared spectrum
