Growth and morphology of ruby crystals with unusual chromium concentration (original) (raw)
Related papers
The growth of ruby single crystals
Journal of the Serbian Chemical Society, 2005
Ruby (Cr:Al 2 O 3 ) single crystals were grown by the Czochralski technique in an argon atmosphere. The critical crystal diameter d c = 1.0 cm and the critical rate of rotation w c = 20 rpm were calculated by equations of the hydrodynamics of the melt. The rate of crystal growth was experimentally obtained to be 2.7 mm/h. For chemical polishing, conc. H 3 PO 4 at 593 K for an exposure of 3 hours was determined. Conc. H 3 PO 4 at 523 K for an exposure of 3 h was found to be a suitable etching solution. The lattice parameters a = 0.47627(6) nm and c = 1.301(1) nm were determined by X-ray powder diffraction. The obtained results are discussed and compared with published data.
physica status solidi (a), 1985
Mendeleev Institute of Chemical Technology, Moscow1) (a) and Nesmeyanov Institute of Element-Organic Compounds, Academy of Sciences of the USSR, Moscow2) (b) Ruby Structure Peculiarities Derived from X-Ray Diffraction Data Localization of Chromium Atoms and Electron Deformation Density BY V. G. TSIRELSON (a), M. Yu. ANTIPIN (b), R. G. GERR (b), R. P. OZEROV (a), and Yu. T. STRUCHKOV (b) An accurate, X-ray diffraction study is made of the atomic and electronic structure of the ruby crystal A1203:CrS+. Least-squares high-angle refinement (R = 0.0069, R, = 0.0099, S = 1.055) for 180 independent reflections shows that the Cr-atoms substitute the Al-atoms not precisely at the sites of the latter, but are shifted along the c-axis a t a distance of 0.13 A towards the vacant octahedral holes; this is in agreement with aome previous spectral data. I n the electron deformation density map this displacement manifests itself as a peak 0.30 eA-a which is absent in the pure rorundum crystal. The deformation electron density and the electrostatic potential distribution in cuby crystal are analyzed in detail. Es wird eine genaue Rontgenbeugungsuntersuchung der atomaren und elektronischen Struktur des Rubinkristalls Also3: CrS+ durchgefiihrt. Eine Winkelbestimmung nach der Methode der kleinsten Quadrate (R = 0,0069, R, = 0,0099, S = 1,055) fur 180 unabhiingige Reflexe zeigt, dal3 die Cr-Atome die Al-Atome nicht priizise auf deren Pliitze substituieren, sondern auf der c-Achse um die Distanz 0,13 A in Richtung der unbesetzten Oktaederlucken verschoben sind in Ubereinstimmung mit einigen friiheren Spektralwerten. Im Diagramm der Elektronendichtedeformation zeigt sich diese Verschiebung als ein Maximum 0,30 eA-3, das im reinen Korundkristall fehlt. Die Elektronendichtedeformation und Potentialverteilung im Rubinkristall wird ausfiihrlich analysiert .
Ruby Structure Peculiarities Derived from X-Ray Diffraction Data
De Gruyter eBooks, 1985
Mendeleev Institute of Chemical Technology, Moscow1) (a) and Nesmeyanov Institute of Element-Organic Compounds, Academy of Sciences of the USSR, Moscow2) (b) Ruby Structure Peculiarities Derived from X-Ray Diffraction Data Localization of Chromium Atoms and Electron Deformation Density BY V. G. TSIRELSON (a), M. Yu. ANTIPIN (b), R. G. GERR (b), R. P. OZEROV (a), and Yu. T. STRUCHKOV (b) An accurate, X-ray diffraction study is made of the atomic and electronic structure of the ruby crystal A1203:CrS+. Least-squares high-angle refinement (R = 0.0069, R, = 0.0099, S = 1.055) for 180 independent reflections shows that the Cr-atoms substitute the Al-atoms not precisely at the sites of the latter, but are shifted along the c-axis a t a distance of 0.13 A towards the vacant octahedral holes; this is in agreement with aome previous spectral data. I n the electron deformation density map this displacement manifests itself as a peak 0.30 eA-a which is absent in the pure rorundum crystal. The deformation electron density and the electrostatic potential distribution in cuby crystal are analyzed in detail. Es wird eine genaue Rontgenbeugungsuntersuchung der atomaren und elektronischen Struktur des Rubinkristalls Also3: CrS+ durchgefiihrt. Eine Winkelbestimmung nach der Methode der kleinsten Quadrate (R = 0,0069, R, = 0,0099, S = 1,055) fur 180 unabhiingige Reflexe zeigt, dal3 die Cr-Atome die Al-Atome nicht priizise auf deren Pliitze substituieren, sondern auf der c-Achse um die Distanz 0,13 A in Richtung der unbesetzten Oktaederlucken verschoben sind in Ubereinstimmung mit einigen friiheren Spektralwerten. Im Diagramm der Elektronendichtedeformation zeigt sich diese Verschiebung als ein Maximum 0,30 eA-3, das im reinen Korundkristall fehlt. Die Elektronendichtedeformation und Potentialverteilung im Rubinkristall wird ausfiihrlich analysiert .
International Journal of Sciences: Basic and Applied Research, 2016
Purple coloured natural ruby has been studied by surface sensitive tool like XPS supported by XRD, X-ray tomography (micro CT), FESEM, TEM and EDS. While XPS and EDS established the presence of transitional elements like Cr, Fe, Ti, the phases, morphologies and microstructures were studied by XRD, FESEM and TEM. X-ray micro CT provided non-destructive insights into the morpho-structural state of sample. UV-Vis and FTIR spectra of the ruby, recorded both in absorbance and reflectance mode, confirmed the occurrence of the above transitional elements contributing to typical colour display. Core level spectra of Cr, Fe, Ti, Al and O studied by XPS identified the ionic states of the elements. Results of the systematic and detailed investigations carried out in the study conclude that presence of low quantities (trace levels) of Cr, Fe,Ti coupled with intervalence charge transfer between Fe and Ti accounts for the purple colour of natural ruby. The paper further highlights how surface and...
Absorption and emission properties of ruby (Cr:Al2O3) single crystal
Journal of Physics: Conference Series, 2019
Absorption and emission measurement were made on ruby (Cr:Al2O3) crystal with 0.5 wt. %). The results for optical absorption spectra of Cr 3+ :Al2O3 single crystal are shows two strong absorption bands at 408 nm and 558 nm in the range spectrum between 390 nm and 600 nm, meanwhile three broad absorption bands at 205 nm, 227 nm and 255 nm in range spectrum between 190 nm and 370 nm. The emission band when excited by UV light at 205 nm, 227 nm and 255 nm were detected and centered at 321 nm. The emission band by the excitation of 408 nm was found at 465 nm, 671 nm, 692 nm and 710 nm. Meanwhile, the emission band under the excitation of blue light at 490 nm was detected at 671 nm, 692 nm and 710 nm. The emission band at 671 nm, 688 nm, 695 nm and 710 nm were detected from excitation by green light with wavelength at 532 nm and 558 nm.
Single crystal (0001) oriented, sapphire samples were implanted with 150 keV Cr ions at fluences between 6.0×1014 and 4.0×1015 Cr/cm2. The peak concentrations ranged from 0.04 to 0.28 at %. Characteristic photoluminescence of the R lines at 694.3 and 692.9 nm was observed. Annealing at 1450 °C for 2 h increased the luminescence intensity by a factor of 45, due to the increasing fraction of substitutional Cr ions as confirmed by Rutherford backscattering spectrometry. The Cr luminescence decay rate in an annealed sample implanted with 3.0×1015 at/cm2 at 300 K is 299 s−1. Decay rates were also measured for samples covered with a range of transparent liquids (refractive indexn=1.33–1.57), showing a clear increase with increasing refractive index of the liquid. This effect is explained by the increase of the local optical density of states in the Cr-implanted region. By comparing the measured data with the calculated optical density of states the radiative decay rate is found to be 164±10 s−1 and the internal quantum efficiency ∼50%. The quantum efficiency decreases slightly for increasing Cr concentration.
Minerals, 2020
The results of the study of eskolaite associated with marble-hosted ruby found for the first time in the Kuchinskoe occurrence (Southern Urals) are presented. Here, eskolaite was located on the surface and near-surface regions of ruby crystals. Eskolaite diagnostics was confirmed by powder X-ray diffraction (URS-55). The morphology and chemical composition of eskolaite and associated ruby was studied using a JSM-6390LV scanning electron microscope and a Cameca SX 100 electron probe microanalyzer. The eskolaite crystals were hexagonal and tabular, up to 0.2 mm in size. Ruby mineralization was formed during prograde and retrograde dynamothermal metamorphism. The eskolaite associated with the prograde stage ruby contained Al2О3 (9.1–23.62 wt %), TiО2 (0.52–9.66 wt %), V2О3 (0.53–1.54 wt %), FeО (0.03–0.1 wt %), MgO (0.05–0.24 wt %), and SiO2 (0.1–0.21 wt %). The eskolaite associated with the retrograde stage ruby was distinguished by a sharp depletion in Ti and contained Al2О3 (12.25–2...
Beryllium Diffusion of Ruby and Sapphire
Gems & Gemology, 2003
Over the past two years, the heat treatment of corundum involving lattice diffusion of beryllium (Be) at temperatures over 1800°C has become a major issue in the gem trade. Although initially only orange to orangy pink ("padparadscha"-like) sapphires were seen, it is now known that a full range of corundum colors, including yellow and blue as well as ruby, have been produced or altered by this treatment. An extension of the current understanding of the causes of color in corundum is presented to help explain the color modifications induced by Be diffusion. Empirical support is provided by Bediffusion experiments conducted on corundum from various geographic sources. Examination of hundreds of rough and faceted Be-diffused sapphires revealed that standard gemological testing will identify many of these treated corundums, although in some instances costly chemical analysis by mass spectrometry is required. Potential new methods are being investigated to provide additional identification aids, as major laboratories develop special nomenclature for describing this treatment.