Sodium rhodizonate is primarily used as a chemical reagent in analytical chemistry for the detection of heavy metals, particularly lead. It forms a distinctive red precipitate with lead ions, making it highly useful in forensic investigations to identify gunshot residues or lead-based paints. In environmental testing, it helps in detecting lead contamination in soil, water, and other samples. Additionally, it is employed in histology as a staining agent to highlight specific tissue components. Its sensitivity to lead makes it a valuable tool in both industrial and scientific applications for monitoring and identifying lead presence.