Abstract
Synthetic rubies were grown by the optical floating zone method and characterized by cathodoluminescence (CL) microscopy and spectroscopy in combination with microprobe analysis. The measured intensity of the Cr3+-induced CL of corundum is influenced by different parameters such as the sample thickness and orientation, the intensity of the beam current, and the quality of the sample surface. Furthermore, the spectral distribution of the CL emission changes with different concentrations of Cr in the corundum structure. Due to these effects, it is usually not possible to estimate the Cr content directly by using the measured CL intensity. However, we have developed an indirect method that is not significantly affected by these parameters. By using intensity ratios instead of measured intensities, a level of quantification of Cr in natural and synthetic corundum is now possible. Our study shows that the intensity ratio between the N-line at 701.6 nm and the sideband maximum at 713.2 nm displays a nearly linear dependence on the Cr concentration from ca. 100-300 ppm up to ca. 1.1 mol% Cr2O3. These results give a possible approach to develop an optical-microscope-based CL spectroscopy for quantitative measurements of Cr in natural rubies and synthetic α-Al2O3 materials.
© 2015 by Walter de Gruyter Berlin/Boston
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Articles in the same Issue
- Fe site occupancy in magnetite-ulvöspinel solid solutions: A new approach using X-ray magnetic circular dichroism
- Discovery, mineral paragenesis, and origin of wadalite in a meteorite
- Cathodoluminescence microscopy and spectroscopy of synthetic ruby crystals grown by the optical floating zone technique
- Structural relaxation around Cr3+ and the red-green color change in the spinel (sensu stricto)-magnesiochromite (MgAl2O4-MgCr2O4) and gahnite-zincochromite (ZnAl2O4-ZnCr2O4) solid-solution series
- Recrystallization in fully metamict gadolinite from Ytterby (Sweden), annealed in air and studied by 57Fe Mössbauer spectroscopy
- Fantappièite, a new mineral of the cancrinite-sodalite group with a 33-layer stacking sequence: Occurrence and crystal structure
- Reinvestigation of the crystal structure of the zeolite gobbinsite: A single-crystal X-ray diffraction study
- Arsenic-rich fergusonite-beta-(Y) from Mount Cervandone (Western Alps, Italy): Crystal structure and genetic implications
- Crystal structure and low-temperature behavior of “disordered” thomsonite
- Cooling-induced crystallization of microlite crystals in two basaltic pumice clasts
- Crystal structure analyses of four tourmaline specimens from the Cleopatra’s Mines (Egypt) and Jabal Zalm (Saudi Arabia), and the role of Al in the tourmaline group
- Combined single-crystal X-ray and neutron powder diffraction structure analysis exemplified through full structure determinations of framework and layer beryllate minerals
- Olivine crystal size distributions in kimberlite
- Solubility of manganotantalite and manganocolumbite in pegmatitic melts
- The effect of silica on ferric/ferrous ratio in silicate melts: An experimental study using Mössbauer spectroscopy
- HRTEM investigation of trilling todorokite and nano-phase Mn-oxides in manganese dendrites
- Thermo-chemical and thermo-physical properties of the high-pressure phase anhydrous B (Mg14Si5O24): An ab-initio all-electron investigation
- The incommensurately modulated structures of natural natrite at 120 and 293 K from synchrotron X-ray data
- Sulfide oxidation observed using micro-Raman spectroscopy and micro-X-ray diffraction: The importance of water/rock ratios and pH conditions
- In situ measurements of plagioclase growth using SIMS depth profiles of 7Li/30Si: A means to acquire crystallization rates during short-duration decompression events
- Crystal chemistry of the MgAl2O4-MgMn2O4-MnMn2O4 system: Analysis of structural distortion in spinel- and hausmannite-type structures
- The effect of Al and water on the compressibility of diopside
- Geothermometric study of Mg-rich spinels from the Somma-Vesuvius volcanic complex (Naples, Italy)
- Serpentine minerals discrimination by thermal analysis
- A new type of cubic-stacked layer structure in anthoinite, AlWO3(OH)3
- Townendite, Na8ZrSi6O18, a new uranium-bearing lovozerite group mineral from the Ilímaussaq alkaline complex, Southern Greenland
- Letter. Pressure-induced transformations in kaolinite
- Letter. The crystal structure of gypsum-II determined by single-crystal synchrotron X-ray diffraction data