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Crystal Chemical Characterisation of Red Beryl by ‘Standardless’ Laser‐Induced Breakdown Spectroscopy and Single‐Crystal Refinement by X‐Ray Diffraction: An Example of Validation of an Innovative Method for the Chemical Analysis of Minerals
Author(s) -
Tempesta Gioacchino,
Bosi Ferdinando,
Agrosì Giovanna
Publication year - 2020
Publication title -
geostandards and geoanalytical research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.037
H-Index - 73
eISSN - 1751-908X
pISSN - 1639-4488
DOI - 10.1111/ggr.12346
Subject(s) - laser induced breakdown spectroscopy , analytical chemistry (journal) , crystal (programming language) , calibration curve , spectroscopy , chemistry , diffraction , powder diffraction , calibration , x ray crystallography , atomic spectroscopy , atomic emission spectroscopy , materials science , mineralogy , crystallography , detection limit , inductively coupled plasma , optics , chromatography , statistics , mathematics , physics , plasma , quantum mechanics , computer science , programming language
Laser‐induced breakdown spectroscopy (LIBS) is a valuable technique for performing qualitative and quantitative chemical determinations of all elements in one shot, including low atomic number elements such as Li and Be. This technique does not require any sample preparation to reveal the atomic species, even when present in trace amounts (< 0.01% m / m ). In this study, for the first time, we provide an accurate mineral formula for a Cs‐rich red beryl by combining crystallographic data obtained using the traditional single‐crystal X‐ray diffraction technique and quantitative chemical data obtained with an innovative ‘standardless’ method: Calibration‐free‐LIBS (CF‐LIBS). In particular, a new LIBS prototype coupled with a petrographic microscope (CF‐μLIBS) was used to analyse chemically homogeneous areas of about 10 μm spot size, causing minimal damage to the mineral. The results showed that calibration‐free quantitative analysis is suitable for the quantification of major and minor low and high atomic number elements in beryl. The accuracy of quantification of low atomic number elements by CF‐μLIBS led to the empirical formula: [12] (Cs 0.006 Na 0.019 K 0.017 Ca 0.019 ) Σ0.061 [4] (Be 2.989 Li 0.011 ) Σ3.000 [6] (Ti 0.053 Mn 0.051 Mg 0.007 Al 1.890 ) Σ2.000 [4] (Be 0.116 Fe 0.024 Si 5.860 ) Σ6.000 O 18. This formula is consistent with the crystal‐structure refinement data and demonstrates the validity of CF‐μLIBS for chemical analyses of minerals containing low atomic number elements.