ISSN:
1600-5767
Source:
Crystallography Journals Online : IUCR Backfile Archive 1948-2001
Topics:
Geosciences
,
Physics
Notes:
A combination of low-resolution and high-resolution techniques was applied to establish the composition, crystallography and distribution of small inclusions, average diameters 1̃ μm, dispersed within large synthetic diamonds. Both metallic and silicate phases were present among included bodies, often lying adjacent in the same cavity within the diamond matrix. Monochromatic X-ray microradiography, achieving 1 μm resolution with Cu Kα radiation, demonstrated that transition-metal phases constituted a minor fraction of the total volume of inclusions present. In a specimen rich in dispersed inclusions, the sizes of 1483 inclusions were individually measured. In aggregate they occupied 4̃ × 10−4 of the diamond volume. High local inclusion concentrations were associated with high local concentrations of substitutional nitrogen impurity in the diamond matrix. The electron-microscopic techniques included convergent-beam electron diffraction, energy-dispersive X-ray spectroscopy and electron-energy-loss spectroscopy. Detailed crystallographic identifications of individual particles included a b.c.c. Fe–Co alloy (a0 ∼ 2.86 Å), a garnet of andradite variety [a0 = 11.95 (5) Å] and a clinopyroxene with composition corresponding to that in the augite-ferroaugite division of pyroxenes.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1107/S0021889895007370
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