IN PART I OF THIS SERIES we gave a brief introduction to the two localities at Rose Road in the Town of Pitcairn, St. Lawrence County, New York (fig. 2), and presented their detailed history (Chamberlain et al. 2018 Chamberlain, S. C., G. W. Robinson, S. Robinson, M. R. Walter, D. G. Bailey, J. R. Chiarenzelli, and M. Lupulescu. 2018. The Rose Road localities, Town of Pitcairn, St. Lawrence County, New York: Part 1–History. Rocks \& Minerals 93: 442–30.[Taylor \& Francis Online]\ ,\ [Google Scholar]). In Part 2 we provide information about the geology and probable geological origin of both the Wollastonite Skarn and the Purple Diopside Mound