Raman spectroscopic study of various types of tourmalines

Abstract

Both polarized and unpolarized Raman scattering studies of seven tourmalines from the Lucyen mines in Vietnam are presented. These tourmalines, according to their chemical compositions, can be classified into four groups: G1, liddicoatite; G2, elbaite; G3, uvite; and G4, feruvite. The Raman spectra were recorded in two spectral ranges, i.e. 150-1600 cm −1 and 3000-4000 cm −1 . In the lower spectral range, which covers the metal ion-oxygen bond vibrations, all the observed A 1 and E modes are identified. In the higher spectral range, we investigated the OH stretching vibrations and showed that all the observed OH stretching modes have the A 1 character. In both spectral ranges, we found that the same group classification of tourmalines can be applied, and the grouping characterizations are consistent with the chemical composition results.

Electronic structure and anomalous band-edge absorption feature in multiferroicMnWO4: An optical spectroscopic study

“…9,13 Its magnetic phases are characterized by various antiferromagnetic states such that the first antiferromagnetic phase appears below T N3 ≈ 13.5 K. Successive magnetic phase transitions occur at T N2 ≈ 12.5 K and T N1 ≈ 6.5-8 K, forming three different antiferromagnetically ordered phases: AF1 (T ≤ T N1 ), AF2 (T N1 ≤ T ≤ T N2 ), and AF3 (T N2 ≤ T ≤ T N3 ). 14,15 These magnetic phases have been characterized by neutron scattering experiments, which have shown that AF1 has a collinear up-up-down-down spin structure, AF2 has a non-collinear spiral spin structure, and AF3 has a sinusoidal collinear spin structure.…”

“…Moreover, our observation is consistent with the recent Raman studies, where Raman active phonons likewise do not show an anomaly across the magnetic and ferroelectric transition temperatures. 13,31 Therefore, a direct relation between the phonon spectral features and the magnetoelectric coupling properties in MnWO 4 could not be identified.…”

Red gemstone characterization by micro‐Raman spectroscopy: the case of rubies and their imitations

“…Besides garnets as simulant of rubies, among the studied gems, a tourmaline was also identified [sample R14, Fig. (b)] by its Raman spectrum,exhibiting the main peaks at about 377, 730 and 1070 cm −1 …”

“…Besides garnets as simulant of rubies, among the studied gems, a tourmaline was also identified [sample R14, Fig. 3(b)] by its Raman spectrum, [17] exhibiting the main peaks at about 377, 730 and 1070 cm À1 . [18] In the case of sample R11, several strong photoluminescence bands as well as the absence of well-structured peaks were detected, suggesting that the gem was a glass imitation [ Fig.…”

Towards Zn-Dominant Tourmaline: A Case of Zn-Rich Fluor-Elbaite and Elbaite from the Julianna System at Piława Górna, Lower Silesia, SW Poland

“…Raman spectroscopy is a widely applied method for the identification of minerals as well as recognition of their compositional relationships; it is also used frequently in studies of tourmalines [36][37][38][39][40][41][42][43][44]. Because of the particular location of OH groups, which are bound to the octahedral Y and Z cations in the tourmaline structure, the OH vibration bands code crystallochemical information on occupation of both octahedral sites.…”