Crystal field effect on EPR and optical absorption properties of natural green zoisite

Javier-Ccallata, Henry S.; Watanabe, Shigueo

doi:10.1016/j.saa.2012.11.099

Cited by 3 publications

(1 citation statement)

References 28 publications

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“…Transition elements such as V, Cr, Fe, or Mn can replace aluminum and induce color. Vanadium has been found to be the main reason for blue coloration in tanzanite [18], while chromium results in green coloration [19]. Langer et al have reported the UV-Vis spectra of pink zoisite and stated that the reason for the pink color is Mn(III) ions replacing Al in the crystal lattice.…”

Section: Introductionmentioning

confidence: 99%

The Heat Treatment of Pink Zoisite

Schwarzinger

2022

Minerals

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Natural pink zoisites owe their color to a high concentration of manganese paired with low concentrations of other coloring elements such as vanadium or titanium. Upon conventional heating, such stones typically suffer from the reduction of Mn3+ to the colorless Mn2+ species alongside the destruction of the brownish yellow color that is related to titanium. We have processed manganese containing zoisites under the high pressure of pure oxygen which allowed the manganese to remain oxidized, while the brownish yellow color component was still successfully removed. Depending on the vanadium level, the treated gems show a pink to purplish pink color. Detection of this treatment is not easy as the temperature is too low to result in a change in internal features, but a combination of UV-Vis-NIR spectroscopy and trace element chemistry provided by LA-ICP-MS give evidence of such treatment.

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Section: Introductionmentioning

confidence: 99%