Basic Violet 3, universally known as Crystal Violet or Gentian Violet, is a high-purity triarylmethane dye with a deep, brilliant bluish-violet colour. It is closely related to Methyl Violet but is often a purer, single component. Its primary use is in biological staining, most notably as the critical first stain in the Gram staining method. Industrially, its intense colour makes it a powerful colorant for printing inks and paper dyeing.