Orcein is widely used in biological staining, particularly for elastic fibers in tissues. It helps in highlighting these fibers under a microscope, making it easier for researchers and pathologists to study tissue structure and diagnose conditions related to connective tissue. Additionally, it is employed in histology to stain chromosomes and cell nuclei, aiding in genetic and cellular research. Its application extends to the textile industry, where it serves as a natural dye for fabrics, providing unique color tones.