Star salt
From Vanathul Wiki
A shimmering fine powder that seems to shimmer a bit like mother of pearl when it catches the light just right.
Star salt is a drug that grants the imbiber a euphoric feeling in small doses. It is usually ingested nasally, but it will also dissolve in warm water, prompting some to brew it into a potent tea.
In larger doses a fortitude check is called for to prevent some 1d2 wisdom damage and 1d2 charisma damage. This is not particularly high, but habitual over-ingestion cause the DC to gradually increase.
Regardless of the outcome of the save, a large dose like this grants hallusinations/visions of the ethereal plane, and may interact with it to some degree. Equally, denizens of the ethereal may also become aware of a user, and may lash out.