Abstract
The electronic absorption spectra of natural uvarovite containing 62 mole% of the Cr3+ end-member were studied at pressures between 10−4 and ca. 13 GPa using DAC techniques combined with microscope spectrometric device. With increasing pressure, a barochromic effect with change from green to red color of the garnet specimen was observed. This change could be interpreted on the basis of the spectra and the data points derived in an ICE color card. The evaluation of crystal field data from the spectra showed that 10Dq of chromium increases on pressure while the Racah parameter B, and thus the nature of the chemical bond of Cr–O does not change significantly.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Burns RG (1993) Mineralogical applications of crystal field theory, 2nd edn. Cambridge University Press, Cambridge
Eremenko GK, Polkanov YuA (1972) Thermochromic effect in pyrope. Dokl Akad Nauk SSSR 203:1163–1166 (in Russian)
Langer K (1990) High pressure spectroscopy. In: Mottana A, Burragato F (eds) Absorption spectroscopy in mineralogy. Elsevier, Amsterdam, pp 228–284
Langer K, Taran MN, Platonov AN (1997) Compression moduli of Cr3+-centered octahedra in a variety of oxygen-based rock-forming minerals. Phys Chem Minerals 24:109–114
Mao HK (1974) Charge-transfer processes at high pressure. In: Strens RGJ (ed) The physics of minerals and rocks. Wiley, New York, pp 573–581
Neuhaus A (1960) Über die Ionenfarben der Kristalle und Minerale am Beispiel der Chromfarbungen. Z Kristallogr 113:195–233
Ovchinnikov YuI (1975) On the features of thermochromic effect of pyrope. In: Investigations of geology and geophysics of Siberia. Novosibirsk, pp 66–68 (in Russian)
Pool CP Jr (1964) The optical spectra and color of chromium-containing solids. J Phys Chem Solids 25:1169–1182
Taran MN, Langer K, Platonov AN (1996) Pressure- and temperature-effects on exchange-coupled-pair bands in electronic spectra of some oxygen-based iron-bearing minerals. Phys Chem Mineral 23:230–236
Taran MN, Langer K, Platonov AN, Indutny W (1994) Optical absorption investigation of Cr3+ ion-bearing minerals in the temperature range 77-797K. Phys Chem Minerals 21:360–372
Taran MN, Ohashi H, Koch-Müller M (2007) Optical spectroscopic study of synthetic NaScSi2O6–CaNiSi2O6 series pyroxenes. Phys Chem Minerals (in press)
Taran MN, Rossman GR (2002) High-temperature, high-pressure optical spectroscopic study of ferric-iron-bearing tourmaline. Am Mineral 87:1148–1153
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Taran, M.N., Langer, K. & Koch-Müller, M. Pressure dependence of color of natural uvarovite: the barochromic effect. Phys Chem Minerals 35, 175–177 (2008). https://doi.org/10.1007/s00269-007-0209-z
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00269-007-0209-z