Brilliant Blue FCF
![](/Images/godic/202501/01/Brilliant_Blue_FCF_ball-and-stick4657.png")
![In the United Kingdom, Smarties chocolates were colored with Brilliant Blue FCF (top) until 2008, later being replaced with a natural spirulina coloring (bottom).](/Images/godic/202501/01/Blue_smarties4657.JPG")
Brilliant Blue FCF (Blue 1) is an organic compound classified as a Triarylmethane dye, reflecting its chemical structure. Known under various commercial names, it is a colorant for foods and other substances. It is denoted by E number E133 and has a color index of 42090. It has the appearance of a reddish-blue powder. It is soluble in water, and the solution has a maximum absorption at about 628 nanometers.