ALBERT

Description: © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Vigliaturo, R., Elkassas, S. M., Della Ventura, G., Redhammer, G. J., Ruiz-Zepeda, F., O'Shea, M. J., Drazic, G., & Giere, R. Multi-scale characterization of glaucophane from Chiavolino (Biella, Italy): implications for international regulations on elongate mineral particles. European Journal of Mineralogy, 33(1), (2021): 77-112, https://doi.org/10.5194/ejm-33-77-2021.

Description: In this paper, we present the results of a multi-analytical characterization of a glaucophane sample collected in the Piedmont region of northwestern Italy. Investigation methods included optical microscopy, powder X-ray diffraction, Fourier-transform infrared spectroscopy, µ-Raman spectroscopy, Mössbauer spectroscopy, electron probe microanalysis, environmental scanning electron microscopy and energy-dispersive X-ray spectroscopy, and scanning/transmission electron microscopy combined with energy-dispersive X-ray spectroscopy and electron energy-loss spectroscopy. In addition to the crystal–chemical characterization of the sample from the mesoscale to the near-atomic scale, we have also conducted an extended study on the morphology and dimensions of the mineral particles. The main finding is that studying the same particle population at different magnifications yields different results for mineral habit, dimensions, and dimensional distributions. As glaucophane may occur as an elongate mineral particle (e.g., asbestiform glaucophane occurrences in California and Nevada), the observed discrepancies therefore need to be considered when assessing potential breathability of such particles, with implications for future regulations on elongate mineral particles. While the sample preparation and particle counting methods are not directly investigated in this work, our findings suggest that different magnifications should be used when characterizing an elongate mineral particle population, irrespective of whether or not it contains asbestiform material. These results further reveal the need for developing improved regulation for elongate mineral particles. We thus propose a simple methodology to merge the datasets collected at different magnifications to provide a more complete description and a better risk evaluation of the studied particle population.

Description: This research has been supported by the Rotary Foundation (grant no. GG1640842), Javna Agencija za Raziskovalno Dejavnost RS (grant no. P2-0393), Ministry of Education, University and Research, Italy Dipartimenti di Eccellenza (ARTICOLO 1, COMMI 314-337 20 LEGGE 232/2016), and the National Institute of Environmental Health Sciences (grant nos. P30-ES013508 and P42-ES023720).