Extreme redox variations in a superdeep diamond from a subducted slab.

The introduction of volatile-rich subducting slabs to the mantle may locally generate large redox gradients, affecting phase stability, element partitioning and volatile speciation. Here we investigate the redox conditions of the deep mantle recorded in inclusions in a diamond from Kankan, Guinea. Enstatite (former bridgmanite), ferropericlase and a uniquely Mg-rich olivine (Mg# 99.

Fast identification of mineral inclusions in diamond at GSECARS using synchrotron X-ray microtomography, radiography and diffraction.

Mineral inclusions in natural diamond are widely studied for the insight that they provide into the geochemistry and dynamics of the Earth's interior. A major challenge in achieving thorough yet high rates of analysis of mineral inclusions in diamond derives from the micrometre-scale of most inclusions, often requiring synchrotron radiation sources for diffraction. Centering microinclusions for diffraction with a highly focused synchrotron beam cannot be achieved optically because of the very high index of refraction of diamond.

Lanthanite-(Nd), Nd2(CO3)3·8H2O.

Lanthanite-(Nd), ideally Nd2(CO3)3·8H2O [dineodymium(III) tricarbonate octa-hydrate], is a member of the lanthanite mineral group characterized by the general formula REE2(CO3)3·8H2O, where REE is a 10-coordinated rare earth element. Based on single-crystal X-ray diffraction of a natural sample from Mitsukoshi, Hizen-cho, Karatsu City, Saga Prefecture, Japan, this study presents the first structure determination of lanthanite-(Nd). Its structure is very similar to that of other members of the lanthanite group.

Redetermination of durangite, NaAl(AsO(4))F.

The crystal structure of durangite, ideally NaAl(AsO(4))F (chemical name sodium aluminium arsenate fluoride), has been determined previously [Kokkoros (1938). Z. Kristallogr.