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Hi. Val St Lambert are Belgian, and have been in business since the late 1820s to the present day. They had four large factories at one time, along the Meuse valley. They have made paperweights for much of that time (since the 1850s), in limited numbers, and not always with millefiori - there are many cut flash overlay designs. I collect the millefiori :-) .
I think yours might be pre 1930, maybe much older, but I could not be precise.
Alan