A popular stone, especially in the Victorian era and in the African trade. Carefully cut beads came from Idar-Oberstein, as has been discussed before. I haven't trawled the archives, but I know a lot of stuff is there. This type of banded agate also ties in with the whole history of cameos and seals.

A lot of banded agate from China nowadays, presumably to meet demand in Southeast Asia where it seems to have been perennially popular for millenia.

Your carefully matched beads in the first strand seem antique European to me, if only because they aren't as beat-up looking as much older Asian beads.

If you refer to the "Jewellery" page of the linked website, you will find that Scottish agate seems to have been often featured as set cabochon stones rather than beads, perhaps more so than the black and white agate beads and other items cut in Idar Oberstein.