Purplish-red almandine garnets with alexandrite-like effect: causes of colors and color-enhancing treatments

  title={Purplish-red almandine garnets with alexandrite-like effect: causes of colors and color-enhancing treatments},
  author={Klaus Krambrock and Frederico Sousa Guimar{\~a}es and M. V. B. Pinheiro and Roberto M Paniago and Ariete Righi and A. I. C. Persiano and Joachim Karfunkel and Donald B. Hoover},
  journal={Physics and Chemistry of Minerals},
Fine gem-quality, purplish-red garnets from the Tocantins State, Brazil, were investigated for their crystal chemistry and optical properties by several spectroscopic techniques, including electron microprobe analysis, Mössbauer, Raman spectroscopy and optical absorption. Although most garnets are purplish-red, some specimens show color zoning, with deep red color in the core and purple in the outer parts. Electron microprobe analysis showed that these garnets are principally almandine–pyrope… Expand
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