Breaking Bad's 'blue meth' has become iconic in pop culture because of its distinctive color, but what the show doesn't make clear is that pure methamphetamine should actually be colorless. In the series, chemistry teacher turned methamphetamine manufacturer, Walter White, is able to create meth of an extremely high purity, greater than average street meth. The meth is colored blue to signify its purity. In real-world chemistry, substances can acquire a color if their molecular structure absorbs light at a certain wavelength and subsequently emits light at a different wavelength. This effect is the basis for much of organic chemistry, as different molecular structures can produce dramatically different colors. In the specific case of 'blue meth', there isn't any scientific rationale for why highly pure meth would actually be blue. It's generally accepted among chemists that pure methamphetamine should be colorless. So while Breaking Bad gets a lot of the chemistry right, the actual color of the 'blue meth' is fairly implausible. The creators of Breaking Bad actually consulted with the DEA to ensure the chemistry in the show was relatively accurate, but the choice to color the meth blue was done largely for dramatic and symbolic effect. It's highly unlikely that anyone could reproduce this effect in a real-world lab without using some sort of harmless yet highly illegal food coloring. In reality, methamphetamine is dangerous and illegal to manufacture. The chemicals used in its production are extremely hazardous, and the process of making it is highly illegal. The depiction of methamphetamine production on Breaking Bad should be considered fictional and purely for entertainment purposes.