Sawasdee Krub Fred,
Thank you for your comment. I understand that there are a lot of replicas to be careful in all markets nowaday but I am learning to notice the deteriorated glass with calcium stain from some old beads. Can they copie that kind of stain now?

Well, because of my benightedness at the beginning, I did uncarefully put many beads together to clean in the bucket and realized that it's not a good way.

However, it's nice to see you, friends in this forum. If the acid could make glass to be deteriorated with calcium stain as the genuine one, I would stop collecting beads.

Thank you very much again!

Paul