Lots of Swedish (and other) glassworks produced this type of glass with inclusions through the 1950s-70s. It'd be near-impossible to identify it by that alone.
In Sweden, Lindshammar produced a lot of architectural glass - including many door handles and drawer pulls (because of the fitting on yours, these are probably designed for drawers or a cupboard). I've not seen any with inclusions, but they did make a LOT of different handle designs.
Might be worth a look.