Help

I have an international watch company ladies diamond watch. My great great grandmother brought it with her from Germany in about 1920. Wish I would've paid more attention. It has a black face. The face is round it says international on the top and watch company on the bottom. Does anyone know anything about this watch. It cost so much to authenticate I'm just interested. Thank you if so if someone has an idea how much it's worth I really appreciate that too. Thanks again, Renee