I have had a few Washitas like that through the years. While it's true that Arks can come in the same mottled colors I have satisfied myself that most of the ones I have had where indeed Washita's, they came with the Smith's label.The ones I have had were all soft and fast. If there is a problem with them the color changes can be indicators of different hardness areas on the stone and they might wear at different rates and can give you different feed back.