Used as a biological stain in microscopy to enhance contrast in specimens, particularly for staining bacteria and other microorganisms. It is also employed in histology to differentiate tissues and cell structures. In the textile industry, it serves as a dye for coloring fabrics, leather, and paper. Additionally, it is utilized in the preparation of inks and coatings due to its solubility in alcohol and ability to produce deep black shades. Its staining properties make it valuable in research and diagnostic laboratories for visualizing cellular components.