ABSTRACT
In recent years, morganite is becoming more and more popular due to its special color. The morganite samples located in the Republic of Mozambique were detailedly analyzed for its basic properties, chemical composition characteristics and spectroscopy properties by laser ablation plasma mass spectrometry (LA-ICP-MS), ultraviolet-visible absorption spectra (UV-Vis-NIR), infrared spectrum (IR) and Raman spectroscopy. The color parameters of morganite samples including the main wave- length, saturation, and lightness were got by UV-Vis-NIR Chemical composition test showed higher content of Li, Rb, Cs and Mn in samples and chemical formula was calculated as Be3.2090 Al2.0757 Li0.425 Si5.664 O18 (Na0.1420 Cs0.1316). Infrared spectroscopy showed that morganite structure vibration area is mainly in the fingerprint area 400-1200 and 900-1200 cm(-1) for the vibration of the ring Si--O--Si, 550-900 cm(-1) for Be-O vibration area, and 450-530 cm(-1) for Al--O vibration area. Because the Cs element content is higher in sample morganite and Cs belongs to higher atomic number elements, its existence may move the vibrationfrequency of Si--O--Si rings to the low position. Raman spectra showed 1065 cm(-1) for Si-O inner vibration of non bridge oxygen, around 1000 cm(-1) for Be--O outer vibration of non bridge oxygen, 685 cm(-1) for Si--O--Si inner vibration of deformation, 400 cm(-1) for O--Be--O outer vibration of bending, 390 cm(-1) for. Al--O outer vibration of deformation, 320 cm(-1) for Al--O outer vibration of bending.
ABSTRACT
Due to the similarities between mammoth ivory ornaments and modern elephant ivory ones in the market, the spectral properties of the two kinds of ivories were analyzed and compared in the present paper through the gemological tests, infrared spectrum and X-ray powder diffraction, etc. The research found that the refractive index and specific gravity of the two ivories are very similar. The refractive index of mammoth ivory is 1.52-1.53 whereas that of elephant ivory is 1.54-1.55. The specific gravity of mammoth ivory is 1.77 and that of elephant ivory is 1.72. It should be careful that Schreger angles are used to distinguish the two kinds of ivories, because the angles of inner and middle layers in the two kinds of tusks are similar except the angles of elephant tusk out-layers are larger than those of mammoth (The Schreger angle of the sample mammoth ivory belonging to out-layer tusks is 100 degrees nd that of elephant ivory is 115 degrees). In addition, the out-layer Schreger angles of Asian elephants are normally less than 120 degrees, while those of Africa elephants are bigger than 120 degrees (This can be used to identify Asian and Africa elephant ivories). The infrared spectroscopy test shows that the water-molecule-related absorption peaks of 3319, 1642 and 1557 cm(-1) are more obvious in the modern elephant ivory samples than in the mammoth ivory samples; the collagen-related absorption peaks of 2927and 2855 cm(-1) are obvious in the modern elephant ivory but extremely weak in the mammoth ivory. The results indicate that collagen and crystallized water in mammoth ivory reduced to a very low level after having been buried for a long period. X-ray powder diffraction results show that the diffraction peak splits of mammoth ivories are more obvious and sharp than that of elephant ivories, which means hydroxyapatites crystallized better despite being buried for thousands of years. Hence, it is an important reference for identifying the two kinds of ivories that the ivory organic matter was losing and inorganic matter crystallized better at same time after having been buried.
Subject(s)
Elephants , Mammoths , Spectrum Analysis , Tooth , AnimalsABSTRACT
The gemological testing methods, infrared absorption spectrum, Raman spectrum and X-ray powder diffraction were employed to study the gemological characteristics, spectral characteristics and structural features of the "She tai cui" jade. It is indicated that most "She tai cui" jade has the refractive index in the range of 1.53 to 1.54, and a density of 2.65-2.79 cm(-1), and the hardness of 6.5 to 7 in addition to the low hardness (< 5) for the pure white one. The mineral constitution is dominated by quartz in most of the "She tai cui" jade, except the white one, which is dominated by dolomite (about 63.91%). The former may contain a certain amount of other impure minerals and is attributed to the quartzite jade, while the latter contains a certain amount of SiO2 (about 34.85%) and a trace amount of calcite and albite, and is attributed to the dolomite jade.
ABSTRACT
The nephrite species with different colors from Xinjiang and Xiuyan, Liaoning, including gray nephrite, yellow nephrite, white nephrite, jasper and He-Mo nephrite, a special nephrite from Xiuyan, were selected for the present study. The gemological testing method, infrared absorption spectroscopy and X-ray powder diffraction were used to analyze and compare the gemological characteristics of the nephrite with different colors and textures from the above localities, in order to understand the similarities and differences between these nephrites with similar colors but different origin, and provide a theoretical basis for the identification of the nephrite origin. The results show that the nephrites from Xinjiang and Xiuyan, Liaoning province have similar gemological properties. They have similar refractive index of 1.60-1.62 and density of 2.660-3.020 g x cm(-3), and only the density has some differences with different colors. The fluorescence.characteristics are not obvious in these nephrites. The major constituent minerals for these nephrites are tremolite, and small amounts of clay minerals such as chlorite and illite are found in the jasper from Xinjiang. Based on the X-ray powder diffraction analysis on the different types of nephrite from two localities, it was shown that the character of spectra peaks and diffraction intensity of different types of nephrite can reflect the texture of the nephrite and the size of crystalline particles to some extent. The infrared absorption spectra are similar for the nephrites from two localities. The infrared absorption spectrum does not make sense to identify the origin and species of nephrites.
