Is this a female GF?

[gosun]

Recently i bought a pair of GF. The female's head is black with some patches of red. Is it a female? why this mutation on head color?

any comments?

[CandoAviary]

Sounds like a female. Most times females will not have a strong red mask. I have seen many that at first glance looked like a black head...but on closer inspection were indeed red head.
You can also determine hens by the yellow of the belly being lighter than the male, also not as much blue around the collar. The purple will not be as bright or rich in color either.