On a number of Japanese auction sites, you can find this vintage lamp by using the right search terms:

The design is fun, the lamp is dimmable, and I'd guess it's from the '80s or '90s. It has a surprising provenance:

Did the cosmetics brand Shiseido have a line of lighting? Not as far as I know. The lamp is occasionally listed with the words "Diamond Class Souvenir," and I did find one instance of the lamp being sold with documentation; on the back, it clearly says "Not for sale." So perhaps this was made as a gift for clients or distributors.

The lampshade, which was clearly molded in two pieces, has this odd slit in the top:

My only guess is that the slit is for cooling.

Lastly, the dimensions of the lamp:

If they made this lamp today for retail, I bet it'd sell. I think if a cosmetics influencer had this in one of their shots, it'd be a matter of time before knockoffs appeared on Alibaba or Temu.