Thankyou! It's so good to have found here. I will go and introduce myself in the thread up above.

Now that I see the glass examples posted above I can see that it's obvious mine are not glass. But all the other pictures I had seen of agate and carnelian, the striations weren't as regular as mine. Your answers took me to the mines in Brazil and an explanation of why these are so regular. This is just lovely - it's everything I like all rolled into one!

Can I ask now, how can you tell how old these are? If Idar-Oberstein has been making these traing beads for so long, how can I have an idea of where mine might fit in. Now that I know how they're made, under an eyeglass i can see the cutting machine striations, and from another old discussion of holes on this board I can see that holes were drilled first from one end and then the other because they slightly don't meet up in the middle. But how can I guess their age?

Thanks again

Johanna