# Portable Raman Spectrometer for In Situ Analysis of Asbestos and Fibrous Minerals
## 4 Conclusions  
pRS has proved to be a reliable, affordable, and easy-to-use instrument for the identification of mineral fibers on the mining front, under several different geological and environmental conditions. Raman spectra acquired with pRS at both low- (bulk modes) and high-wavenumbers (OH-stretching) had an adequate spectral resolution and signal-to-noise ratio to allow the identification of the main varieties of asbestos and asbestos-like  
Figure 5: Raman spectra of a bundle consisting of chrysotile (circle assignment) and fibrous antigorite (asterisk assignment) collected with portable Raman. The contribution of OH-stretching of the two phases occurred simultaneously. A comparison with Raman spectra collected with HRS is reported in Supplementary Material S5. minerals during in situ surveys. In this respect, a portable Raman equipped with a 532-nm laser source and an 8 cm\({}^{-1}\) resolution was proved to be able to obtain spectra in the required spectral range (100-4000 cm\({}^{-1}\)), using a limited amount of time (the instrument is held in contact with the rock by the geologist), on virtually every rock surface. Notably, pRS spectra were of sufficient quality, even in the presence of strongly disaggregated and altered rocks. Fluorescence emission phenomena and the difficulty to focus the laser beam on a non-cohesive bundle of fibers are the main contingencies that can impair the analysis. Relatively easy training for the use and data interpretation is required for operators (e.g., professional geologist). The following are available online at [[https://www.mdpi.com/2076-3417/11/1/287/s1](https://www.mdpi.com/2076-3417/11/1/287/s1)]([https://www.mdpi.com/2076-3417/11/1/287/s1](https://www.mdpi.com/2076-3417/11/1/287/s1)), Figure S1: Schematic for Portable Raman Instrument (pRS); Figure S2: XRPD Qualitative bulk analysis, Figure S3: Representative Raman spectra of non-asbestos phases collected with portable Raman Spectrometer (pRS); Table S1: Assignment of peaks in the Raman spectra at low- and high-wavenumber regions of investigated asbestos and asbestos-like minerals; Figure S4: Raman spectra of a bundle of intermixed chrysotile and fibrous antigorite collected with portable Raman (pRS) and micro-Raman spectrometer (HRS). Conceptualization, J.R.P., F.T. ; methodology, J.R.P., D.B., F.T. ; investigation, J.R.P., M.T., C.L.-M., A.C., D.B. ; resources, M.T., C.L.-M., A.C., D.B. ; writing--original draft preparation, J.R.P. ; writing--review and editing, J.R.P., D.B., E.S.-M., C.L.-M., A.C., F.T. ; supervision, C.L.-M., E.S.-M., A.C., D.B., F.T. ; funding acquisition, M.T., F.T. All authors have read and agreed to the published version of the manuscript. This study was supported by Amiante et Bonnes Pratiques (ABP) project, funded by CNRT \"Nickel and its environments\" of New Caledonia. The pRS was jointly acquired by M.T. with the ABP project and University of Parma resources. [PERSON]'s post doc position is funded by the INAIL--BRIC 2019 project, grant number ID 57.1. Not applicable. The data that support the findings of this study are available from the corresponding author, [PERSON], upon reasonable request. The authors are indebted to Balangero RSA srl (Italy) and Societe Miniere \"George Montagnat\" (New Caledonia) for permission to access the study sites, for the accompaniment and relevant discussions in the field. The photograph used in the table of contents graphic is courtesy of RSA, Balangero, Italy. The authors kindly acknowledge [PERSON] for fruitful discussion throughout the writing stage. The authors declare no conflict of interest. References
NIOSH. The National Institute for Occupational Safety and Health (NIOSH). Available online: [[https://www.cdc.gov/niosh/pubs/default.html](https://www.cdc.gov/niosh/pubs/default.html)]([https://www.cdc.gov/niosh/pubs/default.html](https://www.cdc.gov/niosh/pubs/default.html)) (accessed on 28 November 2020). * IAEG (2020) IAEG. Commission NOA EMP Commission--AEG NOA Technical Working Group & IAEG NOA Commission.