Researchers use spectroscopic methods to characterize ancient Egyptian mining gemstones

In a recent study published in the journal AIP Advances, researchers used molecular and elemental spectroscopy techniques such as laser induced breakdown spectroscopy (LIBS), Raman spectroscopy, and Fourier transform infrared (FT-IR) spectroscopy to characterize mines in ancient Egypt.

In this study, researchers examined various gemstones that can be traced back to the era of the pharaohs. The team analyzed gemstone samples such as olivine, beryl/emerald, Tianhe stone, and amethyst to learn more about their chemical composition. Doing so can give researchers a better understanding of ancient Egyptian history, which may help determine the trade routes of ancient civilizations. Researchers compared these gemstones with olivine samples found in the Harat Kishb lava field in western Saudi Arabia.

Gems are valuable artifacts in archaeology. Gemstones have significant historical and cultural significance. By discovering ancient gemstones, archaeologists can use them to piece together what ancient society may have looked like and the values of people living in that era. These cultural relics reflect both cultural significance and visual beauty. However, finding an effective and efficient detection method to distinguish between natural gemstones and synthetic gemstones may be challenging, and spectroscopic techniques may be helpful in this process.

For example, LIBS is an effective technique that can distinguish different gemstone groups. By analyzing specific spectral windows, researchers identified the unique characteristic elements of each gemstone variety. Raman spectroscopy and Fourier transform infrared spectroscopy can also serve as valuable tools to provide unique molecular fingerprints that indicate possible changes over time. FT-IR even revealed specific functional groups in these gemstones that present charming colors.

In this study, three experimental methods were used, with each spectral technique using one method. The experimental setup for LIBS analysis involves the use of a Q-switched Nd: YAG laser with a wavelength of 1064 nm. The Eschelle spectrometer is coupled with an ICCD camera and LIBS software is used to analyze LIBS spectra. FT-IR analysis was performed using the 4100 Jasco spectrometer in the vibration range of 400-4000 cm-1 wavenumber, using potassium bromide as a reference. Raman analysis was performed using a confocal Raman microscope manufactured in Germany under the conditions of 473/532/633 nm laser excitation, z-focusing, and software controlled X-ray sample stage for line scanning and mapping.

Gem enthusiasts, historians, and gem traders will benefit from their ability to track the origin and authenticity of gemstones, allowing them to glimpse the ancient past.

Source: Laser Network