This miniature of an unknown man has been attributed to Samuel Folwell (1765-1813) who worked in various east coast cities and died in Philadelphia. Folwell was trained as an engraver and the fine detail on this miniature, especially on the jacket buttons, supports an artist trained in this manner.
There is a miniature portrait which appears to be by the same artist in the Worcester Art Museum, see fig 68 in Strickler's "American Portrait Miniatures" although that portrait is unattributed.
It is also a profile portrait, painted around 1795, of a man (George W Tuckerman) with a queue tied with a ribbon. That miniature is on paper, but is housed in a similar ebonised frame with an identical hanger, which itself is of an uncommon and plain design.
The sitter in this miniature is unknown. 1244