The pre-snow rain that came early this afternoon washed the slate dust from the roof and revealed the subtle tricolor palette. The darker slate is Vermont Black. The lighter of the three is Unfading Green, and the color in between is Unfading, Mottled, Purple and Green. In time, various lichens and mosses will contribute to a rich patina that will develop during the life of the roof which can be up to a century. There are definite sustainable advantages to using slate for a roofing material and certainly no other product is more organic in origin.