There are other scales, such as the Dorian mode (1-2-b3-4-5-6-b7), but the minor pentatonic and natural minor are the ones we usually learn first. By contrast, the harmonic minor has a unique ...

Harmonic minor keys are used when writing chords. There is another version of the minor key known as the melodic minor. This is used when writing a melody. Each key signature has two possible keys.