Spectral, electron microscopic and chemical investigations of gamma-induced purple color zonings in amethyst crystals from the Dursunbey-Balkesir region of Turkey

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dc.contributor.authorHatipoǧlu M.
dc.contributor.authorKibar R.
dc.contributor.authorÇetin A.
dc.contributor.authorCan N.
dc.contributor.authorHelvac C.
dc.contributor.authorDerin H.
dc.date.accessioned2024-07-22T08:20:13Z
dc.date.available2024-07-22T08:20:13Z
dc.date.issued2011
dc.description.abstractAmethyst crystals on matrix specimens from the Dursunbey-Balkesir region in Turkey have five representative purple color zonings: dark purple, light purple, lilac, orchid, and violet. The purple color zonings have been analyzed with optical absorption spectra in the visible wavelength region, chemical full trace element analyses (inductively coupled plasma-atomic emission spectroscopy and inductively coupled plasma-mass spectroscopy), and scanning electron microscopic images with high magnification. It can be proposed that the production of the purple color in amethyst crystals is due to three dominant absorption bands centered at 375, 530, and 675nm, respectively. In addition, the purple color zonings are also due to four minor absorption bands centered at 435, 480, 620, and 760nm. X-ray diffraction graphics of the investigated amethyst crystals indicate that these crystals are composed of a nearly pure alpha-quartz phase and do not include any moganite silica phase and/or other mineral implications. Trace element analyses of the amethyst crystals show five representative purple color zonings, suggesting that the absorption bands can be mainly attributed to extrinsic defects (chemical impurities). However, another important factor that influences all structural defects in amethyst is likely to be the gamma irradiation that exists during amethyst crystallization and its inclusion in host materials. This gamma irradiation originates from the large underlying intrusive granitoid body in the region of amethyst formation. Irradiation modifies the valence values of the impurity elements in the amethyst crystals. It is observed that the violet-colored amethyst crystals have the most stable and the least reversible coloration when exposed to strong light sources. This situation can be related to the higher impurity content of Fe (2.50ppm), Co (3.1ppm), Ni (38ppm), Cu (17.9ppm), Zn (10ppm), Zr (3.9ppm), and Mo (21.8ppm). © 2011 Taylor & Francis.
dc.identifier.DOI-ID10.1080/10420150.2011.553283
dc.identifier.issn10294953
dc.identifier.urihttp://akademikarsiv.cbu.edu.tr:4000/handle/123456789/18057
dc.language.isoEnglish
dc.subjectAbsorption
dc.subjectAtomic spectroscopy
dc.subjectChemical analysis
dc.subjectColor
dc.subjectCrystal defects
dc.subjectCrystal impurities
dc.subjectCrystals
dc.subjectEmission spectroscopy
dc.subjectGamma rays
dc.subjectInductively coupled plasma
dc.subjectIrradiation
dc.subjectLight absorption
dc.subjectLight sources
dc.subjectMass spectrometers
dc.subjectMass spectrometry
dc.subjectMolybdenum
dc.subjectOptical emission spectroscopy
dc.subjectQuartz
dc.subjectTrace elements
dc.subjectX ray diffraction
dc.subjectX ray diffraction analysis
dc.subjectZirconium
dc.subjectZoning
dc.subjectamethyst
dc.subjectDursunbey-Balkesir
dc.subjectgamma irradiation
dc.subjectICP-AES
dc.subjectICP-MS
dc.subjectOptical absorption spectroscopy
dc.subjectpurple quartz
dc.subjectSEM
dc.subjectTurkey
dc.subjectXRD
dc.subjectAbsorption spectroscopy
dc.titleSpectral, electron microscopic and chemical investigations of gamma-induced purple color zonings in amethyst crystals from the Dursunbey-Balkesir region of Turkey
dc.typeArticle

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