Welcome Rolf,
Please feel free to post in the ID section.
There are a number of European collectors that frequent this sight and they can help with many that you may have found in your home country.
Post two or three marbles at a time and take multiple shots of the marble. Size is important as well.
We all love a good ID ask here and look forward to you participation.
Once again a most hardy welcome and of course---
Marble--On!!