 Because "diatonic scale" is itself ambiguous, distinguishing intervals is also ambiguous.For example, the interval B–E (a diminished fourth, occurring in C harmonic minor) is considered diatonic if the harmonic minor scale is considered diatonic; but it is considered chromatic if the harmonic minor scale is "not" considered diatonic.Forte lists the chromatic intervals in major and natural minor as the augmented unison, diminished octave, augmented fifth, diminished fourth, augmented third, diminished sixth, diminished third, augmented sixth, minor second, major seventh, major second, minor seventh, doubly diminished fifth, and doubly augmented fourth.