Thank you for the suggestions. Actually, I had tried both tests when I first got the bangle, but I tried them again after reading your post. But no there's no sign of any soft compound that I can find. I probed at the juncture of the stone and glass but there was no give there. And down to the right of the repair in the close-up there's a round spot or altered surface in the stone, so I tried scraping away at it with a sharp point, but after several minutes none of it scraped away or even scratched.

I have other things from the same period that have been repaired with some kind of "glue" of the time - a form of resinous proto-lacquer, I guess - but those repairs have invariably dried out, cracked and flaked away - nothing like this. My own impression is that heat has been applied in the process or repair.

Incidentally, the photo - though it's more in focus than most of my work! - is actually a bit misleading. The stone and the glass in fact are much more translucent than they appear, and the marks on the stone stand out less.

Will