Three historical `asteriated' hydrogen-rich diamonds: growth history and sector-dependent impurity incorporation

Research areas:
Year:
2004
Authors:
Journal:
DIAMOND AND RELATED MATERIALS
Volume:
13
Number:
9
Pages:
1658-1673
Month:
September
ISSN:
0925-9635
BibTex:
Abstract:
Three historical `asteriated' diamond slices present mixed-habit growth
with contemporaneous lobe-shaped cuboid sectors and octahedral sectors.
The lobe shape is explained by continuous variation of the relative
growth rates. Nitrogen concentration in octahedral sectors is higher
than in cuboid sectors, whereas hydrogen is incorporated mostly in
cuboid sectors. The H-related IR peak at 3236 cm(-1) peak, and the two
peaks at 3050 and 3154 cm(-1) (which may be completely absent from the
spectra) are independent from the well-known 1405-3107 cm(-1) system.
Nitrogen aggregation during thermal history seems partially inhibited in
cuboid sectors by the large amount of hydrogen, as platelets and N3
centres are present in octahedral sectors but not in cuboid sectors.
Cuboid, H-rich growth sectors are thought to appear when the amount of
hydrogen in the medium is too high to be incorporated in the octahedral
sectors only. The definition of `H-rich diamonds' is revisited. The
first-order Raman peak at 1332 cm(-1) is slightly growth-sector
dependent; cuboid sectors show a sharper and more Lorentzian peak than
octahedral sectors. (C) 2004 Elsevier B.V. All rights reserved.