How old is this little mirror?

Chokwe mirror

I’m currently researching a Chokwe divination basket from Angola and among the many objects it contains I encountered the above mirror (ca. 4 cm high). Clearly it’s European, but I would like to find out how old it actually is. So don’t hesitate to get in touch if you have an idea. Thanks.

UPDATE: A Portuguese reader send me several pictures of related mirrors made in the 1950s-1960s by two Portuguese companies named LUSO and OSUL. Another reader from Portugal dates the style of the portrait to the 1920s. A last reader informed me that in 19th century Spain it was a tradition to give these vanity mirrors (with a female print on the back) as a present to a lover.  Though of a different theme, the OSUL mirror is indeed very similar in construction. The Portugal- Angola connection does support this line of reasoning. Thanks all !

OSUL mirror Portugal

LUSO mirror Portugal