The history of lava lamp is currently very well known due to a large amount of research in this area. But similar research regerding the history of glitter lamp has, as far as i know, never been performed. Due to this fact, we do not know who invented it and when did it happen. Here are some guesses on the subject.
1. Did the inventor of glitter lamp know about such a device as snow globe? The answer is definitely "yes", since snow globes, according to Wikipedia, originate from the 1800s (btw, their inventor, who lived in France, is also unknown);
2. Did the inventor of glitter lamp know about bubble type Christmas lights? The answer is also definitely "yes", since they were invented in 1935;
3. Did the inventor of glitter lamp know about lava lamp? Here, the answer is "maybe yes, maybe no", because it is unknown whether glitter lamp was invented after or slightly before lava lamp (which happened in 1963). But probably after, so let's consider that the answer here is also "yes";
4. What elese? Maybe the mirrored disco ball? While being completely different from glitter lamp, it produces a very similar image on walls. Did the inventor of glitter lamp know about it? Again, the answer is definitely "yes". Wikipedia tells that disco ball was first mentioned in 1897.
Now the next question. Why did the inventor combine these four already known devices into one "hybrid" called glitter lamp? In other words, for which purpose did the inventor invent it? I have one guess.
The patents! Many manufacturers wished to produce a device that looks like a lava lamp, or even more dazzling and spectacular, but without waiting for its patents to expire. And that's why someone invented the glitter lamp for them.
But who was that "someone"? Does any information exist on the subject?