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Crystal Violet

Crystal Violet

Ionisation: Basic

Chemical structure of Crystal Violet

Common Name: Crystal violet
Suggested Name: Crystal violet
Other Names:

Gentian violet Methyl violet 10B

C.I. Number: 42555
C.I. Name: Basic violet 3
Color: Blue-violet
Solubility Aqueous: 1.68%
Solubility Ethanol: 1.68%
Absorption Maximum: 593 (Gurr), 588 (Aldrich)
Empirical Formula: C25H30N3Cl
Formula Weight: 408


Crystal violet is the deepest blue of all the methyl violets, and is satisfactory for most purposes for which methyl violet is used, including the metachromatic demonstration of amyloid. Its darker blue shade makes it the dye of choice for use in Gram's stain for the demonstration and primary classification of bacteria. Although it has been used in the past as a bacteriostatic agent for topical skin application, Aldrich lists this dye as a cancer suspect agent.

The name gentian violet is given to many of the dyes in this general group, and can not be relied upon to give any consistency in identification. It is preferable to avoid the name altogether.


  1. R. D. Lillie.
    Conn’s Biological Stains
    Williams & Wilkins, Baltimore, MD., U.S.A.
  2. Edward Gurr, 1971
    Synthetic dyes in biology, medicine and chemistry
    Academic Press, London, England.
  3. Aldrich chemical catalogue, 1992
    Aldrich Chemical Company, Milwaukee, WI, USA.