I've seen and handled a few of these over the years and as I've been rereading this thread and thinking about them, "Japan" was starting to shout loudly in my brain - before I saw Steven's response.
I've only recently learned a bit about Japanese bits of glass and seen how they're finished and how they feel - and now I'm putting my recent learning in conjunction with my memories of these, I reckon they belong together.
I have serious doubts about them being any older than the '50s..... 1950s.