I bought one of these in an Emmaus Brocki in Switzerland a couple of years ago.
Looking through the base, it's just the standard candleholder with a chromed, flanged stem glued onto the top (i.e. not into the candle socket). The bit that holds the bulb is black plastic, and screws into the chrome tube. The glass hasn't been drilled at all.
It makes a great lamp. Heavy and stable.