Fossil resins are often used to indicate the botanical origins of ancient plants through their secondary metabolites. However, the existing chemotaxonomy of fossil resins is limited in its ability to distinguish them at phylum, family, and genus levels using small amount of samples. Herein an advanced head-space solid phase microextraction- comprehensive two-dimensional gas chromatography- time-of-flight mass spectrometer platform was established to analyze the complex compositions of resin fossils derived from ancient gymnosperms (e.g., Eocene Cupressaceae, Cretaceous Araucariaceae) and angiosperms (Miocene Dipterocarpaceae and Miocene Hymenaea). The secondary metabolites including 83 monoterpenes, 186 sesquiterpenes, 84 diterpenes, and 43 n-alkanes were annotated and then chemically fingerprinted for the first time. Prior to conducting chemical composition classification, this study tested the vitrinite reflectance of resin-bearing rocks and Tmax of the ambers to demonstrate their similar thermal maturity. After that, chemotaxonomic markers were disclosed using multivariate statistical analysis to identify the botanical origins of resin fossils, and four identification rules were concluded. Gymnosperm and angiosperm resins can be distinguished by the relative content of monoterpenes and diterpenes. Eocene Cupressaceae and Cretaceous Araucariaceae resins can be identified by ten chemotaxonomic markers which were screened out by orthogonal partial least-squares regression. Miocene Hymenaea and Dipterocarpaceae resins have different combinations of chemical superclasses, with sesqui- and di-terpenes being the major compositions of Hymenaea resins, and mono- and sesqui- terpenes accounting for most of the compositions of Dipterocarpaceae resins. Specific chemotaxonomic markers can identify Hymenaea mexicana and Hymenaea protera resins. As the chemical components of fossil resins were determined by the genes present in their botanical origins, the chemotaxonomic markers revealed in this study have a genetic basis. These findings provide a comprehensive database of secondary metabolites from ancient resin plants, which can be utilized for further research on their corresponding paleoenvironment and to clarify their phylogeny.
"Ice jade" is a translucent variety of jadeite jade (also known as fei cui) that is generally of high value. Reportedlyfrom the Morales mine in the Izabal Department of Guatemala, it has recently appeared in the Chinese jewelrymarket. In this study, the structural characteristics, mineral compositions, and color genesis of Guatemalan "icejade" were studied using scanning electron microscopy, cathodoluminescence, X-ray diffraction, electron probemicroanalysis, Raman spectroscopy, and ultraviolet/visible/near-infrared spectroscopy. "Ice jade" is composed al-most exclusively of jadeite, with accessory minerals that include omphacite and albite. The chemical compositionof the samples studied here was nearly pure sodium pyroxene. A small amount of fine-grained omphacite imparteda pale green color to this material. This "ice jade" exhibited fine-grained texture, occasionally with some micro-granular texture. Guatemalan "ice jade" has a unique characteristic appearance, microstructure, accessory min-erals, and chemical compositions, but further study is needed to distinguish it from the other origins
蜜蜡是一种黄色-棕色的半透明至不透明琥珀,老蜜蜡是指经历了一定时间(几十至上百年)的佩戴、盘玩或搁置在自然环境下经风化作用使颜色变深,视觉上显"老"的蜜蜡,因其具有较高的文化价值和商业价值,深受收藏者和大众的喜爱,且存量有限,其价格一直居高不下.近年来市场上出现了大量的用普通蜜蜡经加热处理,通过控制加热的速率、温差等参数,或者叠加了其他技术而形成的人工做旧老蜜蜡,其外观近似年代久远的老蜜蜡.目前学术界缺乏对人工做旧老蜜蜡的系统性研究.本文采用宝石显微观察、红外光谱、光致发光光谱、紫外-可见-近红外光谱对清代自然老化老蜜蜡与人工做旧老蜜蜡进行了系统研究,总结了二者的鉴别特征.主要结论如下:(1)人工做旧老蜜蜡表面大多光滑,有时可见快速加热形成的黑色碳化凹坑等,有些人工做旧老蜜蜡也可人工打磨出较一致的凹凸不平外观,而 自然老化老蜜蜡大多表面粗糙,具有不规则凹凸不平的外观;(2)人工做旧老蜜蜡的龟裂纹只能做出一组,且裂隙较老蜜蜡形态规则,裂纹可大、可小,深度较浅;自然老化老蜜蜡的龟裂纹形态自然、均匀、紧密,一般分为2～3级,1级主裂隙深而宽,显微镜下呈深色大裂隙,2级裂纹的深度和宽度小于主裂纹,3级细微龟裂纹分布于被主裂纹或2级裂纹分割成的小块区域内.自然老化老蜜蜡的3级或2级龟裂纹同时存在,是人工做旧老蜜蜡目前无法实现的工艺,也是鉴别它们的重要依据;(3)人工做旧蜜蜡断口处的老化层厚度(≤ 0.2 mm)远小于自然老化老蜜蜡(≥0.8 mm);(4)红外光谱中,自然老化老蜜蜡的由于表面粗糙,红外光谱变形明显,"波罗的海肩"(1 260～1 160 cm-1)不显著,而该特征峰在人工处理老蜜蜡中则较明显,与其老化层过薄有关.其次,1 566 cm-1处的吸收峰在 自然老化老蜜蜡中出现的几率较高,推测与波罗的海琥珀老化后生成的琥珀酸有关.(5)老蜜蜡和人工做旧老蜜蜡的光致发光光谱相似,但两种样品的发光中心强度比断口处(内芯)均有大幅下降,详细对比二者的特征谱峰波长有较小的差异,但易受仪器精度和人为操作影响,鉴定意义需进一步统计验证;(6)紫外-可见-近红外光谱二者基本一致,没有鉴定意义.本文的研究结果对自然老化和人工处理的老蜜蜡鉴别有实用价值.
宝石学是学科交叉融合的特色学科,经过30多年的发展,取得了辉煌的成就,但也存在隐忧和问题.当前宝石学教学中存在的问题主要为:教学体系中整体偏重于鉴定环节,鉴定教学中又偏重知识点的传授,对方法的教学和创新式教育引导不足;科研与教育、产业结合尚显不足;科研成果发表难度大;教师晋升通道有待通畅等.笔者通过国内外高校的对比调研,认为应适时开展"从矿区原石到市场首饰"的全产业链教学,并分析了必要性.全产业链教学应主要从学科交叉融合、教学内容覆盖全产业链;产教结合,协同发展;实验标本的可靠收集与信息化建设;提升思政教育、服务于行业发展需求等方面进行.
汉字有着鲜明的图形特征,汉字进行图形化的处理后,形意得到了巧妙的转换,同时传达了字意之外的情感,从而产生了丰富的视觉语言.笔者通过对汉字图形在首饰设计中借形与达意的表现形式、二者的美学共通性进行研究分析.对汉字笔画、结构进行分解,利用块、面、体重新组合,最终完成从汉字图形的转化,并将汉字"羊"进行图形化处理后应用在首饰设计中,展现汉字图形在首饰设计中的设计思路.
