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Article type: Cover
1992 Volume 17 Issue 1-4 Pages
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Article type: Index
1992 Volume 17 Issue 1-4 Pages
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Article type: Index
1992 Volume 17 Issue 1-4 Pages
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ichiro Sunagawa
Article type: Article
1992 Volume 17 Issue 1-4 Pages
3-9
Published: December 15, 1992
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Natural diamond grew in silicate solution, whereas synthtic diamond grows in metallic solution, both at high temperature and high pressure conditions. The solvents are different between the two, which leads to a difference in morphological characteristics. Gem quality natural diamonds are single crystalline, in which {111} face is always an atomistically smooth interface on which spiral growth can occur, whereas {100} is an atomistically rough interface and no spiral growth can take place. On the contrary, both {111} and {100} faces behave as smooth interfaces in the groivth of synthetic diamonds and exhibit growth spirals. The difference comes from the difference in solvents. As a result ofsuch differences between the two, natural and synthetic diamonds exhibit different growth sectors and growth banding, which can be used as diagnostic features to differentiate natural and synthetic diamonds, if appropriate methods to visualize these heterogeneities and imperfections in single crystalline cut stones, such as polarization microscopy, cathodoluminescence tomopography, Iaser beam tomography, etc. are applied. Morphological characteristics of synthetic diamonds by CVT method are also described.
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Takeshi Miyata, Masao Kitamura
Article type: Article
1992 Volume 17 Issue 1-4 Pages
10-15
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Studies on growth zoning of diamond have revealed that (1) growth morphology of natural diamonds consists of flat {111} faces with or without curved {100} faces whereas that of synthetic diamonds consists of flat {111} and {100} faces, and (2) each diamond has its own patterns of growth zoning. The present observation of the zoning on facetted diamonds by using a cathodoluminescence microscope also confirmed these characteristics. These characteristics as "finger print"can be used in the identification of individual diamond and in descrimination whether a diamond is natural or synthetic. A convenient index system to arrange the zoning patterns was proposed.
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Hisao Kanda
Article type: Article
1992 Volume 17 Issue 1-4 Pages
16-23
Published: December 15, 1992
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The largest diamonds are 15mm across in the world. They are large onough to be distributed in a gem market, and it is interesting how they are distinguished from natural crystals. Color is a factor to characterize the crystals, and this paper reviews studies on atomic impurities, which influence optical properties, in synthetic diamonds. Nitrogen content can be controlled by choosing composition of metal catalysts, and a colorless crystal is obtained using a metal catalyst containing nitrogen getters such as titanium. Growth temperature and annealing temperature are also parameters which control concentration and structure of nitrogen. Boron is easily incorporated in grown crystals, producing blue color, if it is present in the growth cell. Depth of blue color depends on metal catalysts and boron content in the cell. Nickel is also incorporated in diamonds, and induces green or brown color. These impurities are inhomogeneously distributed in the crystals.
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[in Japanese]
Article type: Article
1992 Volume 17 Issue 1-4 Pages
23-
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Mutsukazu KATO
Article type: Article
1992 Volume 17 Issue 1-4 Pages
24-30
Published: December 15, 1992
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This paper reports outline of diamond synthesis from gas phase and some properties of diamond prepared by the microwave plasma method which have been studied using Raman, absorption and cathodoluminescence spectroscopies, and secondary ion mass spectroscopy (SIMS) analysis. It has been shown that single crystals have good crystalline quality. In contrast, the polycrystalline films grown under the same conditions have appreciable amounts of double bonds and strain. SIMS analyses have indicated that contamination by elements of substrate holder cannot be neglected for the diamond obtained, that contents of hydrogen and oxygen are negligible small, that other impurities with concentration highor than that in natural diamond are not detected.
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Iwao Umeda, Koichi Iida
Article type: Article
1992 Volume 17 Issue 1-4 Pages
31-36
Published: December 15, 1992
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It is well known qualitatively that colorloss diamonds can be artificially colored to green by irradiation using a research reactor, and that the green colored diamonds may fade the color to faint yellow by heat treatment at the temperature of 300℃ and over. The purposes of this examination are, however, to find the conditions quantitatively (10^<14>〜10^<16> fast neutrons/cm^2 ,300〜700℃), and moreover, to make coloration to black at first by high dose irradiation of 3×10^<16>〜1×10^<17> fast neutrons/cm^2 using a research reactor, and to change the black color to orange〜Iightred-brown by subseqent heat treatment at the temperature of 600〜700℃.
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[in Japanese]
Article type: Article
1992 Volume 17 Issue 1-4 Pages
36-
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Masahiko Hayashi, Yutaka Horikawa
Article type: Article
1992 Volume 17 Issue 1-4 Pages
37-42
Published: December 15, 1992
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S.T.A.Currio (1986) summarized previously reported equations to calculate the weight of a round brilliant cut diamond. All these are appoximate equations, assuming limited conditions. We propose in this paper a new equation to evaluate the weight of a round brilliant cut more precisely, which is applicable to less limited conditions. the weight (ct) = 0.004853203×H・(D^2+D・T+T^2) -0.0007107349 ×T^2・(H-X_2)-0.0003694281×D^2・X_2+0.01380337×D^2・G-0.000004975073×D^3・((H・X_2)/(1.961571×(D -T)・X_2-0.1493155×D・H)+(P・Y)/(1.961571×D・Y-0.1493155×P・D)) +0.004853203×D^2・P-0.0003694279×D^2・Y X_2= (0.1522409×D・H・(D-T)+1.847759×H√<{(D-T)^2+3.414214×H^2}・U^2-0.03806023×D^2・H^2>)/(2×(D-T)^2+3.414214×H^2) Y=(1-(1.847759×L)/(√<D^2+3.414214×P^2>))・P In this equation, D is the diameter of the girdle, P is the depth of the pavilion, G is the thickness of the girdle, H is the height of the crown, U is the length between the vertical point of the star facet and the girdle, L is the length between the vertical point of the lower girdle facet and the vertical point of the pavilion and T is the diameter of the table in mm. This equation appears very complicated, but the calculalian is easy by the use of a calculator.
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[in Japanese]
Article type: Article
1992 Volume 17 Issue 1-4 Pages
43-44
Published: December 15, 1992
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[in Japanese]
Article type: Article
1992 Volume 17 Issue 1-4 Pages
44-
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Article type: Bibliography
1992 Volume 17 Issue 1-4 Pages
45-57
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Article type: Bibliography
1992 Volume 17 Issue 1-4 Pages
58-67
Published: December 15, 1992
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[in Japanese], [in Japanese]
Article type: Article
1992 Volume 17 Issue 1-4 Pages
68-
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[in Japanese]
Article type: Article
1992 Volume 17 Issue 1-4 Pages
68-69
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[in Japanese]
Article type: Article
1992 Volume 17 Issue 1-4 Pages
69-70
Published: December 15, 1992
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[in Japanese], [in Japanese], [in Japanese]
Article type: Article
1992 Volume 17 Issue 1-4 Pages
70-
Published: December 15, 1992
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[in Japanese], [in Japanese]
Article type: Article
1992 Volume 17 Issue 1-4 Pages
70-71
Published: December 15, 1992
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[in Japanese], [in Japanese], [in Japanese]
Article type: Article
1992 Volume 17 Issue 1-4 Pages
71-72
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[in Japanese]
Article type: Article
1992 Volume 17 Issue 1-4 Pages
72-
Published: December 15, 1992
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[in Japanese], [in Japanese]
Article type: Article
1992 Volume 17 Issue 1-4 Pages
72-
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[in Japanese]
Article type: Article
1992 Volume 17 Issue 1-4 Pages
72-73
Published: December 15, 1992
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[in Japanese], [in Japanese], [in Japanese]
Article type: Article
1992 Volume 17 Issue 1-4 Pages
73-
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[in Japanese]
Article type: Article
1992 Volume 17 Issue 1-4 Pages
73-
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[in Japanese]
Article type: Article
1992 Volume 17 Issue 1-4 Pages
73-74
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[in Japanese], [in Japanese], [in Japanese]
Article type: Article
1992 Volume 17 Issue 1-4 Pages
74-75
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[in Japanese], [in Japanese], [in Japanese]
Article type: Article
1992 Volume 17 Issue 1-4 Pages
75-
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[in Japanese], [in Japanese], [in Japanese]
Article type: Article
1992 Volume 17 Issue 1-4 Pages
75-
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Article type: Appendix
1992 Volume 17 Issue 1-4 Pages
76-80
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Article type: Appendix
1992 Volume 17 Issue 1-4 Pages
81-84
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Article type: Appendix
1992 Volume 17 Issue 1-4 Pages
85-
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Article type: Cover
1992 Volume 17 Issue 1-4 Pages
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Article type: Cover
1992 Volume 17 Issue 1-4 Pages
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