Local relaxation around [6]Cr3+ in synthetic pyrope?knorringite garnets, [8]Mg3[6](Al1?X CrX3+)2[4]Si3O12, from electronic absorption spectra

Taran, Michail N.; Langer, Klaus; Abs-Wurmbach, I.; Frost, Daniel J.; Platonov, A. N.

doi:10.1007/s00269-004-0424-9

Cited by 31 publications

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“…It was found that no single phase of garnet was observed over the entire range of the present P -T conditions up to 16 GPa and 1800 °C, in contrast to earlier studies by Ringwood (1977), Irifune et al (1982), Taran et al (2004), and Klemme (2004), where the formation of pure knorringite was reported at pressures higher than 8 -12 GPa. In the present study, knorringite is subjected to majorite substitution at pressures above ~ 8 GPa, which exhibits a behavior similar to that observed in pyrope at lower pressures (Ringwood, 1967;Ringwood and Major, 1971;Liu, 1977;Ito and Takahashi, 1987).…”

Section: Phase Relations In Mg 3 Cr 2 Si 3 O 12contrasting

confidence: 99%

“…Moreover, the univariant reaction MgCr 2 O 4 + 2Mg 2 Si 2 O 6 = Mg 3 Cr 2 Si 3 O 12 +Mg 2 SiO 4 , has a negative slope in the P -T space between 1200 °C and 1600 °C. Similarly, Taran et al (2004) confirmed the coexistence of ~ 3% eskolaite in the knorringite sample synthesized under similar pressure and temperature conditions except for one run at 11 GPa and 1400 °C, where the synthesis of pure knorringite was reported.…”

Section: Introductionsupporting

confidence: 72%

“…In the present study, knorringite is subjected to majorite substitution at pressures above ~ 8 GPa, which exhibits a behavior similar to that observed in pyrope at lower pressures (Ringwood, 1967;Ringwood and Major, 1971;Liu, 1977;Ito and Takahashi, 1987). However, the substitution behavior in knorringite found in the present study differs from that reported by Ringwood (1977), Irifune et al (1982), Taran et al (2004), and Klemme (2004), where no majorite component was found in knorringite. In addition, we also found that the chromium content in garnet and eskolaite decreased significantly with increasing pressures from 8 GPa to 16 GPa at 1600 °C.…”

Section: Phase Relations In Mg 3 Cr 2 Si 3 O 12supporting

confidence: 63%

“…Figure 3 shows the phase relations in Mg 3 Cr 2 Si 3 O 12 based on the present high pressure and high temperature experiments, where the formation of an assemblage of majoritic knorringite (Mj -kn) + eskolaite (Es) was observed at pressures above ~ 8 GPa at 1600 °C with a neg- Tables 1 and 2). For comparison, the previous results of Irifune et al (1982), Turkin et al (1983), Taran et al (2004), Klemme (2004), andJuhin et al (2010) are also shown in this phase diagram. Our results are quite different from the earlier studies by Irifune et al (1982), Turkin et al (1983) and Klemme (2004), where the synthesis of a single phase of pure knorringite was reported.…”

Section: Phase Relations In Mg 3 Cr 2 Si 3 O 12supporting

confidence: 54%

“…The successful synthesis of knorringite garnet was first reported by Coes (1955) in a brief communication, in which neither the synthetic method nor the physical properties of this novel garnet was specified. Since then, many scientists have shown great interest in experimental studies of the phase stability and synthesis of knorringite -rich garnet (e.g., Bykova and Genshaft, 1972;Ringwood, 1977;Irifune et al, 1982;Turkin et al, 1983;Taran et al, 2004;Juhin et al, 2010). Ringwood (1977) reported the synthesis of knorringite garnet at pressures from 8 GPa to 16 GPa and temperatures of 1400 -1500 °C.…”

Section: Introductionmentioning

confidence: 99%

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Phase relations in Mg3Cr2Si3O12 and formation of majoritic knorringite garnet at high pressure and high temperature

Zou

Irifune

2012

Journal of Mineralogical and Petrological Sciences

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High -pressure and high -temperature phase relations for Mg 3 Cr 2 Si 3 O 12 have been studied at pressures from 8 to 16 GPa and temperatures of 1200 -1800 °C using a Kawai -type multianvil apparatus. The low -pressure phase assemblage of MgSiO 3 pyroxene + Cr 2 O 3 eskolaite was found to transform into a high -pressure phase assemblage of majoritic knorringite + eskolaite with a negative phase boundary of dP/dT = −0.010 GPa/°C. No pure Mg 3 Cr 2 Si 3 O 12 knorringite garnet was observed over the entire range of the P -T conditions in the present study, suggesting that pure knorringite garnet may not be a stable phase under these pressure and temperature conditions. This result is inconsistent with earlier studies, where knorringite was reported to be stable at pressures higher than ~ 10 GPa. On the other hand, the present result agrees well with recent results for the synthesis of majoritic knorringite at pressures of 11 and 14 GPa and at temperatures of 1500 -1600 °C. Majoritic knorringite becomes more Cr -deficient with increasing pressure, which is similar to the Al -deficient nature of majoritic garnet in the MgSiO 3 -Al 2 O 3 system.

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Section: Phase Relations In Mg 3 Cr 2 Si 3 O 12contrasting

confidence: 99%

Section: Introductionsupporting

confidence: 72%

Section: Phase Relations In Mg 3 Cr 2 Si 3 O 12supporting

confidence: 63%

Section: Phase Relations In Mg 3 Cr 2 Si 3 O 12supporting

confidence: 54%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Phase relations in Mg3Cr2Si3O12 and formation of majoritic knorringite garnet at high pressure and high temperature

Zou

Irifune

2012

Journal of Mineralogical and Petrological Sciences

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Pigments Based on Perovskite

Ardit

Cruciani

Dondi

et al. 2015

Perovskites and Related Mixed Oxides

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Quantitative definition of strength of chromophores in gemstones and the impact on color change in pyralspite garnets

Sun

Palke

Renfro

et al. 2022

Color Research & Application

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The color of most garnets is derived from multiple color‐producing elements (chromophores). In this study we selectively isolate the ultraviolet–visible–near infrared (UV–Vis–NIR) spectra of four major chromophores (Fe2+, Mn2+, Cr3+ and V3+) by collecting and extrapolating the spectra of four representative pyrope‐almandine‐spessartine (pyralspite) garnets. In order to study the color strength of these isolated chromophores and their impact on color change in garnet, we have proposed a new quantitative definition of strength of a chromophore. With the isolated garnet chromophore spectra, hypothetical garnet spectra with various chemical compositions can be simulated. By using these hypothetical garnet spectra, the impact of each chromophore on the color change behavior in pyralspite garnet was also quantitatively studied. Most pyralspite garnets can be successfully modeled using these four chromophores, however, this model cannot adequately describe those garnets containing the Fe3+/Fe2+ intervalence charge‐transfer transitions. Finally, a comprehensive excel data processing template (Appendix 3) written with VBA macro code was generated to help other researchers calculate colorimetric parameters and color panels from UV–Vis–NIR spectrum. In the template, we provided multiple types of conversion matrices and power distribution curves of different illuminants, so that different colorimetric parameter conversion and color panel calculation from UV–Vis–NIR spectrum can be selected with different combinations based on people's preference. The user guide of the excel template can be found in Appendix 4. The detailed calculation procedures and formulae used for the excel template can be found in Appendix 5.

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Local relaxation around [6]Cr3+ in synthetic pyrope?knorringite garnets, [8]Mg3[6](Al1?X CrX3+)2[4]Si3O12, from electronic absorption spectra

Cited by 31 publications

References 0 publications

Phase relations in Mg3Cr2Si3O12 and formation of majoritic knorringite garnet at high pressure and high temperature

Phase relations in Mg3Cr2Si3O12 and formation of majoritic knorringite garnet at high pressure and high temperature

Pigments Based on Perovskite

Quantitative definition of strength of chromophores in gemstones and the impact on color change in pyralspite garnets

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