It’s this third note (or 3rd as we call it in musical circles ... and the whole mood changes. There are a few types of minor scale, but we’re going to keep things simple and work with the version ...

So the Harmonic Minor’s G# sits perfectly over the E7 chord, outlining its major 3rd. What’s more, this G# also works as a leading note, since it resolves perfectly up a semitone to the root ...