The Black Cheeked mutation changes orange areas into black.
This is an autosomal recessive mutation.
Male Black Cheeked Zebra Finch
The Black Cheeked zebra finch was first discovered in a pet shop in 1984. The owner kept them and bred a good number of them, and didn't sell any until around 1987. The first pairs went for around 2000 Danish kroner (I am not sure what that is in your currency - around 200 British pounds).
The mutation causes all chestnut/orange pigment to change into black. That means that males get black cheeks and black flanks (with the usual white spots). Some (many) poorly coloured specimens have orange in the flanks. This is a show fault. Hens also get black cheeks but the flanks should remain the same as normals. Black flanks on hens is also a show fault (like a breast bar). It is a recessive mutation which means that the best way to produce more is to take a black cheeked and mate it to a good sized normal. That gives 100% normals split for black cheeked. One of these splits should then be mated to a black cheeked, which will give 50% black cheeked and 50% split. Beware of size, as black cheeks have a tendency to be small. Especially mating black cheeked to black cheeked will produce small birds.