A minor plot hole, perhaps, but no doubt an aspect that shows itself to be intrinsically annoying when you consider that Breaking Bad purports to be a show about chemistry, a chemistry teacher, and the illegal drug business - all it once. Plainly put, then: in the real world, the purest form of crystal meth wouldn't - and couldn't - be blue, and none of the chemicals that Walter White uses to render his batches as such would result in blue meth, either. In reality, the purer the meth, the clearer and more see-through in quality. If it were to have a colour tinge as a result of its purity, experts claim that meth would in fact be of a "yellowy" colour. A mere creative embellishment? Sure. But also it's kind of annoying to know that - as far back as its first episode - Breaking Bad failed to stick with any sense of realism regarding crystal meth and its properties.