Used as a staining agent in biological and histological applications to detect calcium deposits in tissues, particularly in bone and mineralized tissue studies. It binds to calcium ions, producing a bright red color that helps visualize calcification under microscopy. Commonly applied in assays for cell differentiation, especially in osteoblast cultures to confirm bone nodule formation. Also utilized in analytical chemistry as an indicator for metal ion detection and in textile industries as a dye for fabrics.