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J. Letendre J.F. Sanvage 1999 Diamonds in volcaniclastic komatite from French Guiana Nature 399
rise to non-equilibrium conditions and the formation of novel structures [ 1 , 2 ]. Of particular interest are impact diamonds ( Fig. 1 ) and diamond-like nanostructures that form during the shock compression of graphitic materials. Fig. 1. Impact
Woloszynek, J. R., Rothbaum, R. J., Rawls, A. S. és mtsai: Mutations of the SBDS gene are present in most patients with Shwachman–Diamond syndrome. Blood, 2004, 104 , 3588
Abstract
Nuclear techniques for the determination of 39 impurity elements in diamonds are described. A common impurity chemistry was found for different diamonds and is considered to reflect the composition of the magma from which they crystallised. A relatively successful attempt was made to differentiate between diamonds from three different kimberlites by the application of discriminant analysis.
Abstract
Instrumental neutron activation analysis (INAA) has been applied to the analysis of 62 small (0.01–0.5 carat), single, inclusion-bearing and inclusion-free diamonds from South Africa, Brazil and Colorado. Up to 40 elements were detected at the ppb and ppt levels in individual diamonds of the eclogitic (basaltic affinity) and the peridotitic (ultramafic) paragenesis. The data obtained in this study can be used to distinguish between diamonds from the eclogitic and peridotitic parageneses and provides geochemical information on the environment in which diamonds crystallize. Further, the technique may prove to be useful in 
fingerprinting
diamonds of different provenance areas.
Abstract
A technique is described for the determination by instrumental neutron activation analysis of the zonal distribution of trace elements in diamond. Individual diamonds were irradiated and then dissolved in stages into 10 to 20 fractions in molten sodium nitrate. The activity of the material dissolved in each fraction was measured using a well-shielded Ge(Li) detector. Because of the small sample sizes involved, many elements typically found in diamond were below the limits of detection even though the experimental conditions were optimised for high sensitivity. The data obtained for a clear, a green and a coated diamond are given here to show the scope of the method. High levels of some elements in the outermost layers of all the diamonds are thought to have been due the implantation of surface contaminants during neutron irradiation. Removal of the outer few microns of irradiated diamonds before counting will avoid this source of error.
Abstract
Techniques for the measurement of low levels of oxygen and silicon, using fast neutron activation analysis, have been developed and applied to high-quality diamonds. For oxygen, a limit of detection of approximately 5 μg has been established. Sources of error have been studied and eliminated, the ubiquitous occurrence of oxygen being the major problem. Within the accuracy of this work, the results obtained show no significant differences in the oxygen contents of diamonds of different types, or of diamonds from different sources. An oxygen content of 35±4 ppm has been established for high-quality colourless diamonds. For silicon, a limit of detection of 25 μg was established and the average silicon content of these diamonds was found to be less than 3 ppm. It is concluded that the oxygen in high-purity diamonds is present as CO2 or H2O and not in silicate inclusions.
Abstract
We show that separable, locally compact spaces with property (a) necessarily have countable extent — i.e., have no uncountable closed, discrete subspaces — if the effective weak diamond principle ⋄(ω,ω,<) holds. If the stronger, non-effective, diamond principle Φ(ω,ω,<) holds then separable, countably paracompact spaces also have countable extent. We also give a short proof that the latter principle implies there are no small dominating families in ω 1 ω.
Abstract
Thirty four elements were determined by instrumental neutron activation analysis in colourless, brown, and pink diamonds, with and without inclusions. These were compared with data obtained for similar elements in the host lamproite rock. The natural radioactivity of these samples was measured by instrumental techniques, and found to be negligible.
Abstract
Thirty-five natural diamonds from six widely differing localities, weighing from 3.6 mg to 305.3 mg were subjected to instrumental neutron activation analysis using high-resolution semiconductor gamma-spectrometry. By means of short-term and long-term activation in a nuclear reactor, Na, Sc, Cr, Mn, Co, La, Ce, Sm, Eu, Hf, Au, Hg, and Th were determined in all the samples, K, Sr, Ag, Cs, Ba, Yb, Lu and W in some, and qualitative determination was carried out with Ca, Fe, Ni, Ga, As, Zr, Sb, Tb, Dy, Ta, It and U. The study serves as a basis for the study of the relationship between the colour, morphology and luminescence of diamonds and their impurity contents.
