High-quality structures at high pressure? Insights from inclusions in diamonds

Angel, R. J.; Milani, Simone; Alvaro, Matteo; Nestola, Fabrizio

doi:10.1515/zkri-2016-1949

Cited by 7 publications

(3 citation statements)

References 19 publications

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“…Data on samples from Damtshaa and Panda were collected at Department of Geosciences, University of Padua, using a Rigaku Oxford Diffraction SuperNova diffractometer equipped with a Mo micro-source X-ray tube and a Dectris Pilatus-200 K detector, controlled by the Crysalis-Pro™ software [Rigaku Oxford Diffraction]. Centring of the inclusion and data collections were performed with a ϕ-scan from 0 to 360° (see Angel et al 2016).…”

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confidence: 99%

Crystallographic orientations of magnesiochromite inclusions in diamonds: what do they tell us?

Nimis

Angel

Alvaro

et al. 2019

Contrib Mineral Petrol

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We have studied by X-ray diffractometry the crystallographic orientation relationships (CORs) between magnesiochromite (mchr) inclusions and their diamond hosts in gem-quality stones from the mines Udachnaya (Siberian Russia), Damtshaa (Botswana) and Panda (Canada); in total 36 inclusions in 23 diamonds. In nearly half of the cases (n = 17), [111]mchr is parallel within error to [111]diamond, but the angular misorientation for other crystallographic directions is generally significant. This relationship can be described as a case of rotational statistical COR, in which inclusion and host share a single axis (1 degree of freedom). The remaining mchr-diamond pairs (n = 19) have a random COR (2 degrees of freedom). The presence of a rotational statistical COR indicates that the inclusions have physically interacted with the diamond before their final incorporation. Of all possible physical processes that may have influenced mchr orientation, those driven by surface interactions are not considered likely because of the presence of fluid films around the inclusions. Mechanical interaction between euhedral crystals in a fluid-rich environment is therefore proposed as the most likely mechanism to produce the observed rotational COR. In this scenario, neither a rotational nor a random COR can provide information on the relative timing of growth of mchr and diamond. Some multiple, iso-oriented inclusions within single diamonds, however, indicate that mchr was partially dissolved during diamond growth, suggesting a protogenetic origin of these inclusions.

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confidence: 99%

Crystallographic orientations of magnesiochromite inclusions in diamonds: what do they tell us?

Nimis

Angel

Alvaro

et al. 2019

Contrib Mineral Petrol

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“…SCXRD experiments carried out in diamond anvil cell (DAC) pose certain experimental difficulties [2,11]. When high pressure is being applied, the mosaicity of the studied crystals usually increases, causing broadening of the diffraction spots and loss of intensity of high-angle reflections [12].…”

Section: Experimental Considerationsmentioning

confidence: 99%

Tracking structural phase transitions via single crystal x-ray diffraction at extreme conditions: advantages of extremely brilliant source

Poręba¹,

Comboni²,

Mézouar³

et al. 2022

J. Phys.: Condens. Matter

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Highly brilliant synchrotron source is indispensable to track pressure-induced phenomena in confined crystalline samples in megabar range. In this article, a number of experimental variables affecting the quality high-pressure single-crystal X-ray diffraction data is discussed. An overview of the recent advancements in X-ray diffraction techniques at extreme conditions, in the frame of ESRF-EBS, is presented. Particularly, ID15b and ID27 beamlines have profited from the source upgrade, allowing for measurements of a few-micron crystals in megabar range. In case of ID27, a whole new beamline has been devised, including installation of double-multilayer mirrors and double crystal monochromator and construction of custom-made experimental stations. Two case studies from ID27 and ID15b are presented. Hypervalent CsI3 crystals, studied up to 24 GPa, have shown a series of phase transitions: Pnma → P-3c1→ Pm-3n. First transition leads to formation of orthogonal linear iodine chains made of I3-. Transformation to the cubic phase at around 21.7 GPa leads to equalization of interatomic I-I distances and formation of homoleptic Inm- chains. The second study investigates elastic properties and structure of jadarite, which undergoes isosymmetric phase transition around 16.6 GPa. Despite a few-micron crystal size, twinning and dramatic loss of crystal quality, associated with pressure-induced phase transitions, crystal structures of both compounds have been determined in a straightforward matter, thanks to the recent developments within ESRF-EBS.

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“…X-ray diffraction (XRD), Synchrotron-based X-ray Tomographic Microscopy (SRXTM) and Alternating Gradient Field Magnetometry. In particular, XRD allows to determine the crystal structure of the inclusions in a repeatable way without altering them [29][30][31][32], while SRXTM is performed to establish which inclusions can be regarded as epigenetic by searching for the potential presence of frac-tures connecting them to the surface all along the diamond interiors [33]. SRXTM allows also to give a reasonable estimate of the linear size, volume and shape of the host-inclusion system, which is an important piece of information to determine more precisely the magnetization of the inclusions or to perform numerical calculations.…”

Section: Introductionmentioning

confidence: 99%

Multi-analytical characterization of Fe-rich magnetic inclusions in diamonds

Piazzi

Morana

Coı̈sson

et al. 2019

Diamond and Related Materials

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Magnetic mineral inclusions, as iron oxides or sulfides, occur quite rarely in natural diamonds. Nonetheless, they represent a key tool not only to unveil the conditions of formation of host diamonds, but also to get hints about the paleointensity of the geomagnetic field present at times of the Earth's history otherwise not accessible. This possibility is related to their capability to carry a remanent magnetization dependent on their magnetic history. However, comprehensive experimental studies on magnetic inclusions in diamonds have been rarely reported so far. Here we exploit X-ray diffraction, Synchrotron-based X-ray Tomographic Microscopy and Alternating Field Magnetometry to determine the crystallographic, morphological and magnetic properties of ferrimagnetic Fe-oxides entrapped in diamonds coming from Akwatia (Ghana). We exploit the methodology to estimate the natural remanence of the inclusions, associated to the Earth's magnetic field they experienced, and to get insights on the relative time of formation between host and inclusion systems. Furthermore, from the hysteresis loops and First Order Reversal Curves we determine qualitatively the anisotropy, size and domain state configuration of the magnetic grains constituting the inclusions.

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High-quality structures at high pressure? Insights from inclusions in diamonds

Cited by 7 publications

References 19 publications

Crystallographic orientations of magnesiochromite inclusions in diamonds: what do they tell us?

Crystallographic orientations of magnesiochromite inclusions in diamonds: what do they tell us?

Tracking structural phase transitions via single crystal x-ray diffraction at extreme conditions: advantages of extremely brilliant source

Multi-analytical characterization of Fe-rich magnetic inclusions in diamonds

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