Notes: C, D, Eb, F#, G, Ab, and B - Key: C - Category: Octatonic Scales
The C Double Harmonic Minor uses eight notes per octave. Because of this same reason it is a member of the so called Octatonic -scales that have Eight-note (or Eight-tone). On the piano keyboard, it is made up of three black keys: Eb, F#, and Ab and four white keys: C, D, G, and B. This combination makes this scale - as well as the C Prometheus, C Prometheus Liszt, and C Prometheus Neapolitan - as great choices for composing or improvising music.
If we take a look a the key signature of the C Double Harmonic Minor Scale we can find it has two flats and one sharps. Therefore, on sheet music you will find three accidentals on the score. The notes of this scale are: C, D, Eb, F#, G, Ab, and B.