This is a tintype, also known as a melainotype or ferrotype; a photograph printed on a thin piece of metal that had been coated with lacquer or enamel. They were most popular during the 1860s and 1870s, but are still made today.
This is known as a. Plate tintype, since it measures about. 2.75 x 3.25. All items are protected in archival sleeves and packaged in rigid cardstock.