p-Rosolic Acid (Aurin) Indicator Grade is a triphenylmethane dye (C.I. 43800) primarily used as an acid-base indicator with a pH transition range of 5.0 (yellow) to 6.8 (pink). It appears as a dark red to brownish-red powder, soluble in ethanol, and is commonly used in laboratory titration, bacteriological media, and microscopy. This indicator is sensitive to pH changes and is often used to detect acidity in clinical or microbiological samples. It should be stored at room temperature.p-Rosolic Acid (Aurin) Indicator Grade is a triphenylmethane dye primarily used as a pH indicator (yellow at pH 5.0, pink/red at 6.8–8.0) in analytical chemistry. It serves as a biological stain in microscopy, a reagent in textile dying, and is utilized in laboratories for detecting coliform bacteria and inducing cellular stress