What is the rarest coat color for a gypsy vanner on howrse?

They come in black, and only black. The only way you might be able to get a different colour is with the 'Golden Apple', or the 'Diamond Apple' but I'm not sure if the 'Diamond Apple' exists anymore. If you use one of the Apples though, the horse will still be classed as it's original colour (with Friesians that will be Back) :)