Crystal violet is a triarylmethane dye.
Crystal Violet is a component of Gram staining that allows one to recognize the difference between gram-positive and gram-negative bacteria with differential staining. The compound helps to access bacterial contamination of tissue culture samples. The staining response is due to the difference in the chemical and structural composition of the cell walls in different bacteria. Crystal Violet can also be used to test the different species of archaea and the cytostatic/cytotoxic effects on tumor cell lines [1][2][3].
References:
[1]. Beveridge, T.J. and S. Schultze-Lam, The response of selected members of the archaea to the gram stain. Microbiology, 1996. 142 ( Pt 10): p. 2887-95.
[2]. Coico, R., Gram staining. Curr Protoc Microbiol, 2005. Appendix 3: p. Appendix 3C.
[3]. Bil, J., et al., Statins potentiate cytostatic/cytotoxic activity of sorafenib but not sunitinib against tumor cell lines in vitro. Cancer Lett, 2010. 288(1): p. 57-67.