There are tons of different kinds of split peafowl, meaning they carry a gene from one or more varieties, but they are not fully that variety...In other words they could look almost like an India Blue, but be split to white.
It can be hard to tell if a bird is split to white or dark pied (split to pied). Generally it has been said that the only way to know if your bird is split or dark pied or split to anything by that matter is by either keeping good records or by breeding the bird and looking to the peachicks to help you figure out what genes the bird is carrying. Needless to say, in my opinion splits are a bit annoying to deal with, but they are pretty. Some of them have flight feathers frosted with white which is unique looking.
Click on the following photos to see a larger version:
Peahens split to white or dark pied (only for reference both peahens RIP)