Collectors have a tendence to make their beads older than they are. Either conciously or - probably more often - unconciously. I am usually interested in facts, not fiction. So please do not misunderstand, when I say my bead - talking about the bigger one with the cracks - should be older than dating from 1960-1970. Why I say or believe so? For one, possibly weak, reason alone: Because I thought that all such beads date back to the 1920's. Since I do not collect such beads, I do not have your level of knowledge here. Are you saying such beads have been made up to the 1960's? That would be a new, but very interesting information. Where do you think probable later types have been made? Germany as well, the country where obviously most specimen of this type come from?

I checked my bead again witha 10x loupe, after reading your post. Though there are slight scratches visible - mostly around both apertures - the bead is basically "like new", refering to the patina alone. It is hard to say if such very few and very light "scratches" stem from use as jewellery (or any other use) or if they are from nothing but handling (without an actual use).

Can I do any amateurish testing in hope to find out more or are you certain it's a PF variety, made any time between 1920 and 1970?

Please refer to any possible production site that might be younger than Germany in the 1920's. Has Germany been the main or only producer 100 years ago? What about France? What about others?