X-ray topographic study of diamonds: implications for the genetic nature of inclusions in diamond

n recent years, several studies have focused on the growth conditions of the diamonds through the analysis of the mineral inclusions trapped in them (Howell, 2012 and references therein). Nevertheless, to obtain rigorous information about chemical and physical conditions of diamond formation, it is crucial to determine if the crys- tallization of the inclusions occurred before (protogenetic nature), during (syngenetic nature) or after (epigenetic nature) the growth of diamond (Wiggers de Vries et al., 2011). X-ray topography (XRDT) can be a helpful tool to verify the genetic nature of inclusions in diamond. This technique characterizes the extended defects and reconstructs the growth history of the samples (Agrosì et al., 2013 and references therein) and, consequently contributes to elucidation of the relationship between the inclusions and the host-diamond. With this aim a diamond from the Udachnaya kimberlite, Siberia, was investigated. The diamond crystal was the one previously studied by Nestola et al. (2011) who performed in-situ crystal structure refinement of the inclusions to obtain data about the formation pressure. The inclusions were iso-oriented olivines that did not show evident cracks and subsequently could not be considered epigenetic. Optical observations revealed an anomalous birefringence in the adjacent diamond and the inclusions had typical “diamond-imposed cubo-octahedral” shape for the largest olivine. The diffraction contrast study shows that the diamond exhibits significant deformation fields related to plastic post growth deformation. The crystallographic direction of strains was established applying the extinction criterion. Section topographs were taken to minimize the overlapping of the strain field associate with the different defects and revealed that no dislocations nucleated from the olivine inclusions. Generally, when a solid inclusion has been incorporated in the growing crystal, the associated volume distortion can be minimized by means the nucleation of dislocations and/or twinning (Agrosì et al., 2013). In our case, the specific and significant features – the olivine inclusions showing a “diamond imposed cubo-octahedral shape” and no dislocation nucleation – that characterize this sample will be discussed in detail

X-ray topographic study of a diamond from Udachnaya: implications for the genetic nature of inclusions

In recent years, several studies have focused on the growth conditions of the diamonds through the analysis of the mineral inclusions trapped in them. In these studies, it is crucial to distinguish between protogenetic, syngenetic and epigenetic inclusions. X-ray topography (XRDT) can be a helpful tool to verify the genetic nature of inclusions in diamond. This technique characterizes, in a non-destructive way, the extended defects within a mineral and reconstructs the growth history of the sample (Agrosì et al., 2013). With this aim a diamond from the Udachnaya kimberlite, Siberia, was investigated. The diamond crystal was the one previously studied by Nestola et al. (2011) who performed in-situ crystal structure refinement of the olivine inclusions to obtain data about the formation pressure. Optical observations revealed an anomalous birefringence in the adjacent diamond and the inclusions had typical “diamond-imposed cubo- octahedral” shape for the largest olivines. The diffraction contrast study shows that the diamond exhibits significant deformation fields related to plastic post growth deformation. Section topographs revealed that no dislocations nucleated from the olivine inclusions. Generally, when a solid inclusion has been incorporated in full-grown state in another growing crystal, the associated volume distortion needs of a number of dislocations to ensure a better connection between the inclusion and the host phase. In some cases, complex twinning can be developed (Agrosì et al., 2013). In our case, the olivine assumes the morphology imposed from the diamond and, consequently, it does not produce volume distortion and the nucleation of dislocations is not necessary. This process generally occur during the simultaneously growth of the two minerals, confirming what was already stated by Bulanova (1995). However, the syngenetic nature of inclusions generally implies epitaxial relationship between diamond and inclusions that in our sample can be ruled out because the orientations of these olivines are random (Bruno et al., 2014). Therefore, the specific and significant results that characterize this sample will be discussed in detail

Application of Laser Induced Breakdown Spectroscopy to the identification of emeralds from different synthetic processes

Laser Induced Breakdown Spectroscopy can provide a useful contribution in mineralogical field in which the quantitative chemical analyses (including the evaluation of light elements) can play a key role in the studies on the origin of the emeralds. In particular, the chemical analyses permit to determine those trace elements, known as fingerprints, that can be useful to study their provenance. This technique, not requiring sample preparation results particularly suitable for gemstones, that obviously must be studied in non-destructive way. In this paper, the LIBS technique was applied to distinguish synthetic emeralds grown by Biron hydrothermal method from those grown by Chatham flux method. The analyses performed by collinear double-pulse LIBS give a signal enhancement useful for the quantitative chemical analyses while guaranteeing a minimal sample damage. In this way it was obtained a considerable improvement on the detection limit of the trace elements, whose determination is essential for determining the origin of emerald gemstone. The trace elements V, Cr, and Fe and their relative amounts allowed the correct attribution of the manufacturer. Two different methods for quantitative analyses were used for this study: the standard Calibration-Free LIBS (CF-LIBS) method and its recent evolution, the One Point Calibration LIBS (OPC-LIBS). This is the first approach to the evaluation of the emerald origin by means of the LIBS technique

Intensive short-term dynamic psychotherapy provided by novice psychotherapists: Effects on symptomatology and psychological structure in patients with anxiety disorders

This study examines the effectiveness of psychotherapy provided by novice therapists, in an attempt to clarify the controversial relationship between treatment effectiveness and therapist experience. To achieve this, we examined the short- and long-term effectiveness of intensive short-term dynamic psychotherapy (ISTDP) in the treatment of patients with the Diagnostic and Statistical Manual of Mental Disorder, IV edition - Text Revision anxiety disorders, as provided by novice psychology trainees. Twenty-two patients with anxiety disorders were provided ISTDP. Patients improved significantly on all outcome indices, including the global assessment of functioning, the symptom checklist and the inventory of interpersonal problems, at the end of the treatment and at 6 and 12 month follow-up. In addition to these results, there was marked structural personality change as evidenced by ratings on the Shedler Westen assessment procedure (SWAP-200), at the same assessment moments; the SWAP-200 psychological health index score showed a meaningful increase in adaptive psychological resources and capacities, while the mean number of personality diagnoses decreased from the beginning to the end of therapy, and all patients maintaining their gains in 6-12 month follow-up. We conclude that ISTDP provided by novice psychotherapists is efficacious in bringing broad and in-depth change to pathology that can perpetuate anxiety disorders and other psychiatric conditions