How long should it take to restore an iPhone 4?

My iPhone 4 was stolen and jail-broken. I have it back now and am trying to restore it to factory default settings. I just did it from the settings on the phone versus doing through my computer. It's been on the black screen with the little white spinning circle for an hour now. I know that there was A LOT of stuff on it so I'm sure it's going to take quite sometimes to restore it. But I'm curious to how long it should take?

You need to restore it via computer. Stay away from the resets in settings as they usually end up causing the iPhone not to boot up. Look up how to put your iPhone if DFU Mode and then restore. The restore process via computer can take up to an hour because it needs to download the firmware and then flash it.