Hi Carlo,
I am a bit to late to check the news and to respond, but maybe it still may be helpful.
I saw osmena pearls in a Chinese shop in the center of Amsterdam, even bought one last winter, and as I noticed last week, they still have them. So, if you ever travel from Germany to Holland, you may look (give me a shout, I'll tell you directions). I also bought one and we discussed it earlier on the forum because I was also confused about its origin (they sell it as blister pearls). It was very helpful and I learned a lot about these pearls. See the thread
Large blister pearl
Best regards
Olga