I called this lady “the hat lady” when sorting through my CdV collection because of all the CdVs I have, I have very few of women in hats. Aside from the hat, she also has a delicate bar pin and some kind of puffy thing, as well as at least a dozen buttons but probably more like 15-18. The photographer was Oleson of 226 & 228 Washington Ave. South, Minneapolis, MN.
UPDATE: from Far Side of Fifty, the Oleson studio was in operation from 1887 to 1889, so we can comfortably date this photo in that range. Thanks!!