USING RAMAN SPECTROSCOPY TO CHARACTERIZE TIO2 POLYMORPHS IN THE JMU MINERAL MUSEUM MICROMOUNT COLLECTION

The James Madison University mineral collection includes over 6,000 micromount specimens containing diverse mineral species. This study aims to evaluate the use of Raman spectroscopy to characterize these micromount minerals. A micromount is a small cluster of crystals in a matrix or a single crystal mounted in a protective enclosure. This research has educational, scientific, and museum curation purposes, and potentially provides a valuable resource for undergraduate research at JMU and the wider mineral community. We selected 30 micromounts containing TiO₂ polymorphs (anatase, brookite, and rutile) from the collection to systematically evaluate the potential of Raman spectroscopy for characterizing micromounts. Spectra were collected using a Renishaw InVia Raman microscope with a 532 nm laser. We conducted spectrum searches and created comparative data plots to identify unique spectra corresponding with specific TiO₂ polymorphs. Additionally, we documented mineral-specific settings to obtain Raman spectra. Challenges for collecting quality spectra arise when inclusions or crystals are less than 10 micrometers or are beneath the surface of the host mineral. Our study demonstrates that Raman spectroscopy can confirm the identity of the mineral written on the label of a micromount, as well as additional minerals not identified on the sample label. We also corrected the identification of some minerals mislabeled in the micromount collection. Raman microscopy is an excellent tool for characterizing micromount collections. Accurate characterization of mineral samples can expand the James Madison University Mineral Museum database. Furthermore, Raman data can be used as documentation in the museum database and potentially shared as standards in existing mineral databases like RUFF, benefiting the broader scientific community.