Nanocrystalline Cookeite from Lithium Mineral Deposits of Jammu, India: A Multianalytical Characterization

This study presents the first integrated micro-Raman spectroscopic and nanoscale investigation of the lithium-bearing bauxite from the Reasi inlier in Jammu. Combined XRD, Raman, FTIR, and high-resolution TEM analyses reveal a mineral assemblage dominated by kaolinite and Li-rich chlorite-group minerals (cookeite), with minor carbonaceous and oxide phases. Powder XRD pattern indicates nanocrystalline intergrowths and mixed-layer domains. Micro-Raman spectra exhibit characteristic Al–O–Si bending and Si–O stretching vibrations diagnostic of kaolinite and cookeite, while FTIR spectra show distinct Si–O and Al–OH bands with broadened Li–O lattice features. HRTEM imaging reveals alternating nanocrystalline and amorphous regions, consistent with partial amorphization and structural reorganization. Energy Dispersive Spectra (EDS) data confirm enrichment of Al, Si, O, and minor Fe, supporting an aluminosilicate framework. These results suggest that kaolinite and cookeite formed through hydrothermal alterations and secondary phyllosilicate formation as a weathering product. Our study contributes to the distribution of lithium minerals which critical for both resource characterization and the development of effective processing strategies.