Used as a humidity indicator in silica gel desiccants, where it changes color from blue (dry) to pink (hydrated) to show moisture absorption. Commonly used in electroplating and metal finishing processes to provide corrosion resistance and wear protection. Employed in the production of catalysts for chemical synthesis, especially in petroleum and organic reactions. Also used in the preparation of cobalt-based pigments and dyes for ceramics and glass. Serves as a precursor in the synthesis of other cobalt compounds in industrial and laboratory settings. Limited use in vitamin B12 production and some biological staining techniques.