Fluid and mineral inclusions in cloudy diamonds from Koffiefontein, South Africa

On the growth of natural octahedral diamond upon a fibrous core

“…One inclusion (e in Table 1) has a composition consistent with enstatite. All these minerals have already been described in inclusions in fibrous diamond [6][7][8][9][10]25,26]. These compositions suggest that the fibrous core derives most probably from a carbonatitic fluid rather than from a hydrous fluid [7,27] or brine [9,10,28].…”

“…This mode of growth is very likely to trap micron-size solid or liquid inclusions between the fibers: this is why such fibrous cubes are often turbid or even opaque. Typical inclusions include water-rich fluids, carbonates, phosphates and silicates [6][7][8][9][10]. The diamond remains nevertheless a single crystal.…”

Fluid inclusions in diamonds from the Diavik mine, Canada and the evolution of diamond-forming fluids

“…Later, totals are renormalized to 100% (on a carbon, water-and carbonate-free basis). Izraeli et al (2004) demonstrated that in spite of the low totals, the precision is good (about 10% relative) and the estimated accuracy is better than 15% for the major elements in the inclusions. Much of the uncertainty in the average composition of individual diamonds is due to real chemical variability between the various micro-inclusions.…”

“…In these cases the crystalline phase dominates the composition of the inclusion that may also include variable amounts of fluid (leading to mixing arrays between the two compositions, cf. Izraeli et al, 2004). Olivine, orthopyroxene, clinopyroxene, garnet, chromite, mica and carbonate were reported in cloudy and fibrous diamonds from South-Africa, Canada and Russia (Tal'nikova, 1995;Izraeli et al, 2004;Klein-BenDavid et al, 2004;Zedgenizov et al, 2004;Klein-BenDavid et al, 2006).…”

The growth of fibrous, cloudy and polycrystalline diamonds

“…Many studies have demonstrated that the major and trace element composition of the inclusions range between one, two or three fluid end-members: silicate, carbonate and aqueous or brine (e.g. Izraeli et al, 2001Izraeli et al, , 2004Klein-BenDavid et al, 2004, 2010Tomlinson et al, 2009;Klein-BenDavid et al, 2010). Another option is a miscibility gap between liquid end-members during multi-stage growth .…”