TY - JOUR

T1 - Application of Raman spectroscopy for identification of rinneite (K3NaFeCl6) in inclusions in minerals

AU - Grishina, Svetlana

AU - Koděra, Peter

AU - Goryainov, Sergey

AU - Oreshonkov, Aleksandr

AU - Seryotkin, Yurii

AU - Šimko, František

AU - Polozov, Alexander G.

PY - 2020/12

Y1 - 2020/12

N2 - Solid daughter phases in fluid and salt melt inclusions in minerals provide important clues to characterization of mineral-forming processes. The analysis of the fluid inclusions often requires the exposure of the daughter minerals. Rinneite (K3NaFeCl6), which is a hygroscopic mineral, decomposes in air and cannot thus be identified by conventional methods. A combined approach has been applied for investigation of synthetic and natural rinneite to acquire its diagnostic Raman spectrum for a nondestructive identification. We used natural rinneite inclusions in halite, suitable for applying a complex of methods, to clear up the reference spectrum. Improved high-resolution X-ray diffraction (XRD) data obtained from natural rinneite inclusion are comparable with that of previously published, with similar unit cell dimensions. Polarized Raman spectra of natural inclusions were obtained using different geometries and polarization of the incident and scattered light. Interpretation of experimental Raman spectra was performed within the framework of lattice dynamics simulations and group analysis. Individual spectral bands are interpreted in terms of Raman-active vibrational modes of K3NaFeCl6 structural units. Raman spectrum of synthetic rinneite with main peaks at 75, 91, 103, 143, 167, 171, 187, and 239 cm−1 agrees well with the spectra of rinneite inclusions in halite from the Nepa potash deposit and rinneite daughter minerals in salt melt inclusions hosted by quartz veinlets from the porphyry gold systems in the Central Slovakia Volcanic Field. This provides a firm basis for any future identification of this mineral worldwide, using nondestructive Raman spectroscopy.

AB - Solid daughter phases in fluid and salt melt inclusions in minerals provide important clues to characterization of mineral-forming processes. The analysis of the fluid inclusions often requires the exposure of the daughter minerals. Rinneite (K3NaFeCl6), which is a hygroscopic mineral, decomposes in air and cannot thus be identified by conventional methods. A combined approach has been applied for investigation of synthetic and natural rinneite to acquire its diagnostic Raman spectrum for a nondestructive identification. We used natural rinneite inclusions in halite, suitable for applying a complex of methods, to clear up the reference spectrum. Improved high-resolution X-ray diffraction (XRD) data obtained from natural rinneite inclusion are comparable with that of previously published, with similar unit cell dimensions. Polarized Raman spectra of natural inclusions were obtained using different geometries and polarization of the incident and scattered light. Interpretation of experimental Raman spectra was performed within the framework of lattice dynamics simulations and group analysis. Individual spectral bands are interpreted in terms of Raman-active vibrational modes of K3NaFeCl6 structural units. Raman spectrum of synthetic rinneite with main peaks at 75, 91, 103, 143, 167, 171, 187, and 239 cm−1 agrees well with the spectra of rinneite inclusions in halite from the Nepa potash deposit and rinneite daughter minerals in salt melt inclusions hosted by quartz veinlets from the porphyry gold systems in the Central Slovakia Volcanic Field. This provides a firm basis for any future identification of this mineral worldwide, using nondestructive Raman spectroscopy.

KW - daughter mineral

KW - Fe-oxyhydroxides

KW - fluid inclusion

KW - rinneite

KW - weathering

KW - FLUIDS

KW - SIBERIA

KW - IRON

KW - CRYSTAL

KW - DEPOSIT

KW - FERRIHYDRITE

KW - SPECTRA

KW - SALT MELT

KW - TRANSFORMATIONS

UR - http://www.scopus.com/inward/record.url?scp=85092100880&partnerID=8YFLogxK

U2 - 10.1002/jrs.6005

DO - 10.1002/jrs.6005

M3 - Article

AN - SCOPUS:85092100880

VL - 51

SP - 2505

EP - 2516

JO - Journal of Raman Spectroscopy

JF - Journal of Raman Spectroscopy

SN - 0377-0486

IS - 12

ER -