This photo is a large tintype, eight by five. The frame it is in is possibly original, but was repainted. I don't know how common large tintypes are, but this one is the only big one I have seen. It has been retouched and is much faded. It appears to have been tinted.
2007: With the help of the Yahoo photoid group, I now think this is an enlargement of an older "CDV" type photo -- card mounted, decorated with fancy squiggles that didn't quite make it onto the enlargement. The enlargement was probably made as a momento after she died.