A venture into the interior of natural diamond: genetic information and implications for the gem industry

Abstract

Natural diamonds are rarely homogeneous. Crystals contain evidence of complicated histories of growth, changes of habit, chemistry, stages of growth and resorption. To extract genetic information recorded during diamond formation they should be studied by modern methods of microanalysis in polished plates. The best way to polish diamond to reveal internal zonation is described and the interpretation of different types of internal morphology of diamonds from cathodoluminescence imagery is given. Knowledge of the internal structures of diamonds is not only useful for scientific observations, but also allows a better determination of their likely behaviour during the cutting and polishing processes. This gives an opportunity for more economic use of individual stones during gem production.

On the growth of natural octahedral diamond upon a fibrous core

“…This is the case of the socalled ''sugar cubes'', for which we could not find any published infrared spectra. This is also the case of diamonds from Yakutiya with the so-called cuboid core [13], and of octahedral diamonds with internal cloudy cores [9,10,[29][30][31]. A detailed study by CL and X-ray topography could highlight their conditions of growth and bring significant insights to the geology of the deposits where they are found.…”

X-ray tomographic study of spatial distribution of microinclusions in natural fibrous diamonds

“…According to the previous studies large mineral inclusions reaching several tens of microns are very rare in fibrous diamonds; they are usually encountered during careful polishing [e.g., 8]. However, X-ray tomography (Fig.…”

“…[8]: high wettability of the diamond by growth medium; B -the inclusions are trapped between diamond fibres (high growth rate; moderate wettability) [19]; C -inclusions concentrate along intersector boundary (this paper).…”

“…the analysed layer is just few microns thick. Already from these works (see, maps of inclusions distribution in [4,8]) it became clear that the inclusions are distributed fairly heterogeneously. Investigation of chemical composition of mineral inclusions is needed for reconstruction of diamond growth medium.…”

FTIR thermochronometry of natural diamonds: A closer look

“…The optimum thickness for diamond seems to be around 300 microns. Diamond plates were prepared in the conventional way by polishing using a diamond impregnated scaife and orienting the diamond parallel to the [110] direction (Bulanova et al, 2005).…”