Cobalt is the 27th element. See Tones of Cobalt for how cobalt is used in the body.

AngstromNanometersColorHertzNoteHertz
2407.256241Ultraviolet566.33D5587.33
2411.624241Ultraviolet565.3
2424.935242Ultraviolet562.2C#5544.365
2521.365252Ultraviolet540.7
3405.118341Ultraviolet400.37G#4415.305
3443.645344Ultraviolet395.89
3453.51345Ultraviolet394.76
3473.974347Ultraviolet392.43
3474.042347Ultraviolet392.42G4391.995
3502.28350Ultraviolet389.26
3526.85352Ultraviolet386.55
3529.808353Ultraviolet386.22
3569.38357Ultraviolet381.94

All of the elements colors are in the ultra violet range. If I take them an octave lower they have the following colors:

Red

Green

Blue

Cobalt Scale

Cobalt Sound Sketch