The Different Inclusions’ Characteristics between Natural and Heat-Treated Tanzanite: Evidence from Raman Spectroscopy
| Autor: | Yingxin Liu, Shuqi Yang, Huijuan Ye |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Anatase
Materials science inclusions General Chemical Engineering Analytical chemistry engineering.material Tanzanite Inorganic Chemistry chemistry.chemical_compound symbols.namesake Pleochroism General Materials Science Graphite Calcite Crystallography heat treatment tanzanite Condensed Matter Physics Prehnite chemistry QD901-999 Raman spectroscopy engineering symbols Inclusion (mineral) |
| Zdroj: | Crystals Volume 11 Issue 11 Crystals, Vol 11, Iss 1302, p 1302 (2021) |
| ISSN: | 2073-4352 |
| DOI: | 10.3390/cryst11111302 |
| Popis: | In this paper, Raman spectroscopy experiments were used to distinguish the characteristics of inclusions (calcite, anatase, graphite etc.) between natural and heat-treated tanzanite. These characteristics were preliminarily divided according to their pleochroism. In natural unheated tanzanite (N5), calcite inclusion is often interspersed with dolomite and has Raman shifts around 156, 283, 710, and 1087 cm−1. In other high temperature treatment samples, the baseline of calcite increased and their Raman peaks gradually shifted towards lower frequencies. Anatase inclusions in natural tanzanite (N5) have four characteristic Raman peaks around 146, 394, 514, and 641 cm−1. Because of the longer Ti-O bond and the wider bond angle distribution caused by high temperature, fewer Raman peaks were observed and the peaks’ intensities were weakened in the heat-treated T7 sample. The black graphite inclusions are often scattered or have a dotted distribution. The most obvious difference between natural and heat-treated samples is that the latter lack the characteristic 1350 cm−1 Raman peak of graphite, thus representing the order and structural incompleteness of graphite. In addition, there are other inclusions in natural unheated tanzanite, such as lead-grey molybdenite with strong metallic luster, randomly scattered prehnite with white dots, orange-yellow rounded rutile, and metallic luster hematite. |
| Databáze: | OpenAIRE |
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