I like the simplicity of this with the variety of the sizes of the stones and the directions of them. There are grays, browns and beiges all blending together. It has the look of strength and history. I would love to see if the stones are only on the chimney or on the cottage exterior. Sometimes simplicity is good in and of itself!
Looking at this picture makes me think how very clever some people are who can arrange rocks/stones/etc. etc. not just for chimneys, but for walls, paths, etc.