What is star dust?

Depends on where you are. In the midwest (of the USA) it refers generally to mephedrone which is the corporate name for a type of plant feed (similar to Miracle-gro) which has effects similar to cocaine and ecstasy.

There isn't an actual "drug name" it's a corporate chemical... and it doesn't stay constant. Everytime the DEA or other authorities make a particular substance illegal they tweak the molecular arrangement and call it something else...

It is SIMILAR to cociane or methamphetamines but much... cleaner would be the word I'd choose... and people who "go crazy" or hallucinate are not doing so because of the drug but instead because they have been awake for too long and are suffering from sleep deprivation.

star dust is actully a metal polishing drug but the effects of taking star dust you have effects of cocaine, pcp, or even extasy

From what I have heard I think stardust is another name for cocaine.