Hello
Agree with Amena that this is European production.
Here are some wildly speculative comments for your consideration:
-Despite the blurry images I see the “Three towers” assay mark from Denmark, and a Georg Jensen maker mark. See mark #8
https://www.925-1000.com/jensen_marks.html
-The handle of the mirror appears to be Jensen’s Pyramid pattern.
-However the 900 mark is puzzling.
-A Google search for Jensen hand mirrors will show you many examples to compare with yours.
Good luck in your research.
Regards.