This is a 9th plate
TinType, hand coloured, and set in an oval matte with ornate frame. It is very typical of Civil War era matting and mounts.
Tintypes were produced in various sizes, and a 9th plate is 2 x 2.5 inches. Tintypes were printed on a single larger sheet of metal and then cut into smaller prints. In this case, 9 prints would have been made of this, printed on a larger sheet of metal and cut into 9 individual tintypes, thus the 9th plate reference.
Often they were trimmed and placed into photo albums. Tintypes can be difficult to date because they were in use from 1855 until the early 1900s. You must use other clues such as clothing, hairstyles, and if you are lucky enough to find one in an album - the type of album and mount used will be an indicator of era.
Source:
Cole Chandler Photo Album in private collection of Lorine McGinnis Schulze