Alizarin is widely used as a dye in the textile industry, especially for dyeing cotton, wool, and silk. It produces shades of red and orange depending on the mordant used, with aluminum mordants giving a bright red color. It is also employed in the production of red lake pigments used in paints and inks. In analytical chemistry, alizarin serves as an indicator for metal ions. It forms colored complexes with metals such as aluminum, calcium, and magnesium, making it useful in detecting these ions in solution, particularly in staining techniques used in microscopy and histology. Alizarin is commonly used in biological staining to identify calcium deposits in tissues. It binds to calcium, producing a distinct red color, which makes it valuable in studying bone growth, calcification processes, and mineralization in biological samples. Additionally, it has been used in the development of pH indicators, changing color in response to acidity or alkalinity, and finds niche applications in the synthesis of other organic dyes and fluorescent compounds.