Studying Tiglit Meteorite Using Raman Spectroscopy and X-Ray Diffraction

A recently published study in the journal Materials provides a comprehensive microstructural and chemical characterization of the Tiglit meteorite, offering fresh insight into the complex formation and alteration history of aubrite-class extraterrestrial materials.¹

What is the Tiglit meteorite?

The Tiglit meteorite is a stony meteorite discovered in the Sahara Desert (often meteorites from this region are named after nearby geographic areas or localities).^1–3 Like other meteorites, it originated from space and survived passage through Earth’s atmosphere before landing on the surface. Six large pieces and many smaller fragments were recovered from where the meteorite landed in the Sahara Desert.³ It is notable for its unusual chemical and mineral composition, which is partially why it is a subject of interest for spectroscopists and astronomers.

What did the researchers do in their study?

Led by researcher Anna Karczemska of Lodz University of Technology, the research team investigated the fragments of the Tiglit meteorite. The team combined scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), Raman spectroscopy, and X-ray diffraction (XRD) to determine the meteorite’s phase and chemical composition.¹ This integrated methodology allowed researchers to characterize both major and trace mineral phases while minimizing sample destruction, which is an important consideration given the scarcity of such materials.

What did the study’s findings reveal?

The findings confirmed the presence of mineral phases typical of aubrites, including pyroxene (enstatite), olivine, plagioclase, sulfides, and iron oxides. However, the study also identified several unexpected components, including calcite and polymorphic forms of silicon dioxide such as quartz and cristobalite.¹ Carbon phases, including nanodiamonds, were also detected, which was notable given that these features are only rarely reported in aubritic meteorites.¹

What do the findings tell us about aubritic meteorites?

Aubrites are a class of meteorites isotopically similar to Earth comprised of magnesium-rich orthophyroxene.⁴ Therefore, it was thought that they resemble the main materials that formed our planet.⁴ The study’s findings, according to the authors, indicate a more complex geological history than previously understood for this class of meteorites.¹ Aubrites are generally believed to form under highly reducing conditions in which free silica is thermodynamically unstable.^1,4 The presence of high-temperature SiO₂ polymorphs therefore suggests that the Tiglit meteorite experienced post-formational processes such as shock metamorphism, transient heating, and rapid cooling.¹

The detection of calcite, meanwhile, appears to be linked to terrestrial alteration processes occurring after the meteorite’s fall. The study suggests that calcite likely formed through the weathering of oldhamite, a calcium sulfide mineral commonly found in aubrites, upon exposure to Earth’s atmosphere. This observation underscores the importance of rapid sample recovery and controlled storage conditions in preserving pristine extraterrestrial signatures.

What did the study reveal about SEM-EDS, XRD, and Raman spectroscopy?

This study showcased both the strengths and limitations of the employed techniques. Although SEM-EDS and XRD provided clear identification of sulfide phases, Raman spectroscopy proved less definitive in this area because of spectral overlap with silicate signals.¹ The authors indicate that further methodological refinement or complementary techniques may be needed to fully resolve these ambiguities.¹

Why are the findings in this study important for material scientists and analytical chemists?

For materials scientists and analytical chemists, the work demonstrates the value of combining multiple microanalytical techniques to interrogate complex, heterogeneous samples. Meteorites, as natural composite materials formed under extreme conditions not reproducible in terrestrial laboratories, offer a unique testing ground for such approaches.¹ The ability to correlate mineralogical phases with their chemical composition at multiple scales is critical for reconstructing both formation environments and subsequent alteration pathways.¹

The study also fills a notable gap in the literature. Despite its classification as an aubrite, the Tiglit meteorite had not previously undergone such a detailed, targeted investigation. By establishing baseline compositional and structural data, the research provides a reference point for future comparative studies of aubritic meteorites and other extraterrestrial materials.¹

References

1. Karczemska, A.; Dudek, M.; Januszewicz, B.; et al. Raman Spectroscopy and X-Ray Diffraction Investigations of Phase Composition of Tiglit Meteorite. Materials 2026, 19 (3), 624. DOI: 10.3390/ma19030624
2. Lunar and Planetary Institute, Tiglit. LPI.USRA.edu. Available at: https://www.lpi.usra.edu/meteor/metbull.php?code=77162 (accessed 2026-04-07).
3. Chennaoui Aoudjehane, H.; Agee, C. B.; Aoudjehane, M.; et al. Tiglit: Aubrite Meteorite Fall in Morocco on December 2021. In 85th Annual Meeting of The Meteoritical Society. LPI Contributions: Houston, 2022; pp. 6352.
4. Peterson, L. D.; Newcombe, M. E.; Alexander, C. M. O’D.; et al. The H Content of Aubrites: An Evaluation of Bulk Versus In Situ Methods for Quantifying Water in Meteorites. Ear. Planet. Sci. Lett. 2023, 620, 118341. DOI: 10.1016/j.epsl.2023.118341