Originally Posted by
Caledonian
It's a wedge razor, and aluminium wasn't produced in bars until the 1850s, or much used commercially until the twentieth century. In the 1880s it cost as much as silver. So I am sure this razor has been rescaled.
It would be extremely clumsy in use as a razor, and one possibility is that it was intended as part of a microtome. This is a device in which a specimen of tissues etc. for microscopic examination is raised very slightly by a screw through a hole in a glass or steel plate, and a thin slice moved by (and on) a very sharp blade.