That particular style of necklace - beads knotted on silk with a brooch-style clasp in the front - seems to have been a popular Chinese jewelry item around the 1920s-30s.

They frequently have some sort of Chinese marking on the back of the clasp. The silver filigree style shows up in old Mandarin hat buttons, so likely there were craftsmen still kicking around who were skilled in doing it, even if the Qing dynasty ended in 1912.

The type of glass or stones typically used seem to fall into the "Chinese" category rather than "European" - note how the murrine in your example do not appear molded, but rather assembled by applying strips of glass around a core. Japanese lampworking method applied by Chinese workmen?

There were a lot of tourists and foreign residents in Shanghai and Peking during those decades, so there was a market for that sort of thing. A melting pot of European, Chinese, and Japanese design?

I suppose they could be Bohemian attempts at a "Chinese" look, and it's hard not to remain skeptical - what do you make of the attached necklace, for instance? Czech or Chinese?