Abstracts of Papers Presented at 2015 Annual Meeting of the Gemmological Society of Japan
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Satoshi Watauchi
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Published: 2015
Released on J-STAGE: October 19, 2015
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Historical aspects of the Center for Crystal Science and Technology (CCST), University of Yamanashi would be introduced. The CCST was established as the Institute of Inorganic Synthesis in 1962. The synthesis of quartz was mainly studied at that time. In 1989, a large high quality single crystal of high-Tc superconductor was successfully grown at this center by the floating zone (FZ) method. This method has been popular to material scientists in the world since then. Now I mainly study the development of the FZ method to realize the manufacturing of a crystal by this method.
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Yasushi Takahashi, Kazuto Koizumi, Yukihiro Yoda, Ryuhei Nataya
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Published: 2015
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The old Cr-Diopside origin is known as a natural monument at Kamisano area southern of Yamanashi prefecture Japan. A new Cr-Diopside deposit is discovered recently. The new deposit area is distributed between Ashiyasu and Kajikazawa area in the west rim of Kofu basin foot of southern Japan Alps.
This study survey both occurrence, and analyzed both hostrock to compare it, and suggest to use Cr-Diopside for jewelry making.
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Masahiko Hayashi, Fujiko Hayashi, Kunihiko Sakamaki, Mana Yasui, Atsus ...
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Published: 2015
Released on J-STAGE: October 19, 2015
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"Hidaka Jade" reported in 1980 by Banba was diopside (CaMgSi
20
6), not jadeite(NaAlSi
20
6). The Hidaka jade is observed most at Chisaka of Hidaka, Saru district, Hokkaido prefecture, Japan. However, cannot be found in the Japanese market at present. The Hidaka Jade occurs between serpentinite and rodingite. As the results of compared with the peridotites from Horoman and Samani districts, the Hidaka jade was found as a new type of jade that was different from these. We examined a mineralogical property of the diopsides and decided to call the Hidaka Jade. These diopsides are attractive coloration gemstones caused by containing Cr ions. We may come to be able to look at the Hidaka Jade in a market in future.
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Masayuki Kawasaki, Mutsumi Kato, Mikuni Hiroi, Ritsuro Miyawaki, Hiroy ...
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Published: 2015
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Natural tapered quartz crystals from Goyomatsu mine (Nara Prefecture) were observed by CL method. Their images show that the growth history was as follows, facet growth, cellular growth and adhesive-type growth, which were related to that of trapiche quartz.
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Ayano Nakajima, Masaki Furuya
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Published: 2015
Released on J-STAGE: October 19, 2015
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Often the faceted beads ablate in the usage. We replicate it with black diamond, spinel and chalcedony in a fixed condition to find the solution to avoid these ablations. The test with metal bar shows a chipping of the facet edge on spinel the most. And the test of beads shows lapping on spinel a lot. The moderately high hardness of spinel may be the reason for such damages.
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Yoshiko Ohe, Seiko Take, Tsuneyo Yamauchi, Kenichi Hata
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Published: 2015
Released on J-STAGE: October 19, 2015
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Jewelry market in Japan will become the period of maturity. The study as the judgement of Gem stones in Japan is the top quality of the world. But the study of Jewelry culture is far behind Europe and America. Now we need to study the history of jewelry and learn the jewelry culture from the birth of the earth. We try to make clear why human being put on Jewelry with a chronological table of jewelry history from ancient times.
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Chihiro Fukuda
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Published: 2015
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Colorless gemstones are commonly used as "Melees" for jewelry. In this study, we try to analyze natural and artificial colorless materials using FTIR. The results indicate that most of tested materials show unique spectrum, and easy to divide into each materials.
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Rie Namba
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Published: 2015
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Taaffeite is known as one of the rarest stone that was discovered in a parcel of faceted stones by Count Taaffe of Ireland in 1945. Although he judged as a piece of spinel with the mauve colour at the first glance, he noticed that the stone showed a slight birefringence. This stone was later confirmed as a new mineral species. Most of the stone exist from mauve to violet, red is reported as rare colour. We have obtained a faceted taaffeite, which is a blue colour from Sri Lanka. The blue is extremely rare since discovery. Taaffeite spectral characteristics are similar to spinel. (Schemetzer et, 1989) Blue is colored with iron or cobalt contents, red is caused by chrome contents. Compared with the spectral characteristics of the spinel and the taaffeite, this exceptional blue colour taaffeite is expected containing cobalt. Therefore we examine it without destruction because of it’s rarity. We are due to report the blue taaffeite properties with some of spinel and taaffeite samples.
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Kowa Kou, Masaki Furuya, Kenichi Hata
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Published: 2015
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We had the analysis to use the tanzanite which are mined at 500 meters underground by the cooperation of ELISARIA MSUYA MAININNG company which owned B block in 4 block in Tanzania.At the first time , we polished the rough stone of Tanzanite which we got at 500 meters underground and then we observed their inclusion by microscope. After that we heated these polished samples each 100°C, 200°C, 300°C, 350°C, 400°C, 450°C and 500°C for 3 hours and got the result for the changing and the data of optical spectrum in comparison with before and after heated. Our purposes of this test is what we must got the sample stones in rough state by the mine directly, because we usually get Tanzanite which had already done heated treatment by low temperature. I chose B block on this time and also examine the ratio of appearance of tanzanite in B block to divide the quality each Gem quality, Jewelry quality and accessories quality into three phases . The market prices are decided the evaluation of the quality and the demand. We report the result of the analysis and the place of origin situation.
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Manabu Kamine, Ravi Abeykoon, Tsuneyo Yamanouchi, Masaki Furuya, Kenic ...
Pages
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Published: 2015
Released on J-STAGE: October 19, 2015
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This time, the gemstone of mine to represent Sri Lanka, which was announced in the last year and availability Gemological Institute (Japan), was carried to a heat treatment at Sri Lanka's local and Japan of two places. Blue Sapphire of treatment before, after the treatment, change of color, change of inclusion, it was further investigated changes in the spectrum of UV-visible spectrophotometer and FTIR.
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Kentaro Emori, Hiroshi Kitawaki
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Published: 2015
Released on J-STAGE: October 19, 2015
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The composition of the gem minerals reflect the geological environment in which the gem mineral yielded. As an application of LA-ICP-MS, we studied geographic origin determination of ruby and blue sapphire. 3D-plot of Mg-V-Fe shows a good indicator to distinguish marble origin rubies (Viet-Nam, Myanmar, Tanzania (Morogoro)) and one of Mg-Fe-Ga shows a good indicator to distinguish basaltic origin blue sapphires (Cambodia, Thailand, China, Nigeria, Tanzania).
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Ikuo Atsumi
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Published: 2015
Released on J-STAGE: October 19, 2015
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According to Dr. Kouji Wada's book "science of a pearl" (1999 Shinju Shinbunsha), it's reported that non-processed Akoya pearls show 3 peaks of absorption at 407nm, 430nm and 460nm on reflection spectrum. It's also stated that these absorption peaks disappear though processing such as heat and alcohol treatment, bleaching and color addition. Therefore, majority of Akoya pearls in the market would not show the above three peaks of absorption on reflection spectrum data.
There are some changes, very small, in Akoya market since the last year. Some Akoya strands are made without any treatments. This attempt is to sell Akoya pearls with natural color condition and also it is expected improvement of durability. Using such non-processed Akoya pearls, we tried to identify them by reflection spectrum. Also we made comparison of both pearls and shells of Akoya and south sea pearls. Then we were able to reach the conclusion that the reflection spectrum analysis is effective to identify Akoya pearls if they are not processed. The reason why Akoya pearls show three peaks of absorption will be also introduced.
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Junko Yazaki, Chiyoko Suzuki, Hiroshi Komatsu
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Published: 2015
Released on J-STAGE: October 19, 2015
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Teri is the most important element about pearls. Various ways have been tried to make pearls with strong Teri by culture of pearls. We have experimented and analyzed some of them , and considered the mechanism strength occurrence in the pearl’s Teri.
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Sayaka Nanjo, Fumika Shoji, Hiroshi Komatsu
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Published: 2015
Released on J-STAGE: October 19, 2015
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The colors of white, orange and purple are generally observed in freshwater pearls, but pearls with dark color also exist. We observed some nucleated freshwater pearls with various colors including orange and purple. We also considered about a transition in a secretion pigment of freshwater pearls.
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Toru Yamamoto, Hirosshi Komatsu
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Published: 2015
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About the characteristic of pearls which shaved the prominence made with the cultured process and shaped
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Toru Katsumata, Kasumi Shiratake, Hiroaki Aizawa, Shuji Komuro
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Published: 2015
Released on J-STAGE: October 19, 2015
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Impurity doped MgAl
2O
4 spinel crystals were grown by floating zone technique. Variations of crystal colors with growth conditions, such as impurities, compositions and O2 concentrations of atmosphere are reported.
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Akio Kawaguchi, Hirofumi Ninomiya
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Published: 2015
Released on J-STAGE: October 19, 2015
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Regarding facet-cut jewels as polyhedral scatterers, their glair should originate from external light source and their efficiency can be discussed as division of light beam. Then, analysis of patterns of scattered beams given by incident of single beam, which is controlled and simulated for general light environment, can suggest correlation with estimation by observers. "Exponential distribution" found for smaller solid angle of scattered beams recognizes efficiency by larger "light spots"; their numerical tendency can be expected for objective estimation of jewels.
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Hiroshi Kitawaki, Mio Hisanaga, Makoto Okano, Kentaaro Emori
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Published: 2015
Released on J-STAGE: October 19, 2015
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Fifteen CVD synthetic diamonds in yellow hues submitted for grading without disclosure were tested in this study. They were proved to be type Ib containing isolated substitutional nitrogen 3.6 ppm on average. From the microscopic observation, the presence of H3 and N3, the H3/NV
- intensity ratio and the absorption peaks due to C-H related defects that were detected in infrared spectral analysis, these stones can be assumed to have undergone annealing about 1900-2200°:C (supposedly HPHT treatment) after the growth.
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