Very interesting (aka educational) thread!

It may be useful, if sometimes boring, to reread lessons that were before, even more than once, explained in the past.
Let both teachers and we students never forget those words from the I Ching: "Perseverance furthers".

Now I have still to disclose a surprising fact: both images show the same imitation amber beads -- a few years in between, and made with different cameras.
The first necklace(with the beads strung as purchased)was undone years ago, and the Yemeni silver disposed off. I am currently into the second project, and of course I would like to be more knowledgeable regarding the material these (nice) beads are made of.