Conclusive comparison of gamma irradiation and heat treatment for color enhancement of Rubellite from Mozambique

Phichaikamjornwut, Bongkot; Pongkrapan, Sorapong; Intarasiri, S.; Bootkul, D.

doi:10.1016/j.vibspec.2019.102926

Cited by 7 publications

(2 citation statements)

References 17 publications

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“…Figure 19 shows a very limited example of the many varieties: a red rubellite , with its colour ascending from the absorption band at ca. 530 nm due to Mn 3+ [ 55 ], and a green tourmaline with an intense absorption band at ca. 710 nm due to Fe 2+ ion and Fe 2+ -Ti 4+ IVCT.…”

Section: Resultsmentioning

confidence: 99%

The Use of UV-Visible Diffuse Reflectance Spectrophotometry for a Fast, Preliminary Authentication of Gemstones

et al. 2022

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The identification of gemstones is an important topic in the field of cultural heritage, given their enormous value. Particularly, the most important precious stones, namely diamond, emerald, ruby and sapphire, are frequently subjected to counterfeit by substitution with objects of lesser value with similar appearance, colour or shape. While a gemmologist is able to recognise a counterfeit in most instances, more generally, it is not easy to do this without resorting to instrumental methods. In this work, the use of UV-visible diffuse reflectance spectrophotometry with optic fibres (FORS) is proposed as a fast and easy method for the preliminary identification of gemstones, alternative to the classical methods used by gemmologists or to Raman spectroscopy, which is by far the instrumental method with the best diagnostic potential, but it cannot be used in situations of problematic geometric hindrance. The possibilities and the limitations given by the FORS technique are critically discussed together with the spectral features of the most important gemstones. Finally, the application of chemometric pattern recognition methods is described for the treatment of large sets of spectral data deriving from gemstones identification.

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Section: Resultsmentioning

confidence: 99%

The Use of UV-Visible Diffuse Reflectance Spectrophotometry for a Fast, Preliminary Authentication of Gemstones

et al. 2022

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“…Although there are many studies on the spectroscopic characteristics of tourmaline and the origin of their colors, they mainly focused on tourmalines with bright colors, such as red, green, and neon blue. In addition, their research methods focused mainly on the spectral line characteristics of transition metal cations [14], or the change in absorption line characteristics with the change in ion states [15,16]. A few studies have been conducted on dark tourmalines, such as blue and purple, and the influence of the occupancy and coordination environment of transition metal ions on the color.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Blue Tourmaline from Madagascar for Exploring Its Color Origin

2022

Advances in Condensed Matter Physics

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In the research, spectroscopic studies of tourmaline for color origin were performed by X-ray diffraction, Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, and X-ray photoelectron spectroscopy. The research work emphasized the analysis of transition metal atoms, including their valence state and coordination number, in order to better understand the effect of transition metal cations on the color origin. The results showed that the blue color of the crystal is caused by the strong absorption at 725 nm in the red spectrum, which generates a symmetrical and wide absorption band. The absorption band at 725 nm is caused by charge transfer between Fe2+ at the Y site and Fe3+ at the Z site. Other ions in the crystal did not generate absorption lines in the visible spectral range. Besides position, its valence state and coordination number were clarified to reveal color variation and the origin of tourmaline. Most importantly, this spectroscopic analysis method makes the coloration mechanism of charge transfer that is difficult to be uncovered to be clearly revealed, which will provide an available material and chemical method to investigate the structure-property relationship for gems as well as reveal the genesis of beautiful colors.

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Gamma irradiation induced degradation of organic pollutants: Recent advances and future perspective

Egerić,

Matović,

Savić

et al. 2024

Chemosphere

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Conclusive comparison of gamma irradiation and heat treatment for color enhancement of Rubellite from Mozambique

Cited by 7 publications

References 17 publications

The Use of UV-Visible Diffuse Reflectance Spectrophotometry for a Fast, Preliminary Authentication of Gemstones

The Use of UV-Visible Diffuse Reflectance Spectrophotometry for a Fast, Preliminary Authentication of Gemstones

Characterization of Blue Tourmaline from Madagascar for Exploring Its Color Origin

Gamma irradiation induced degradation of organic pollutants: Recent advances and future perspective

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