Gold dust is simply pure gold in a very fine particulate form. It doesn't have a specific chemical formula because it's an element, not a compound.

Here's what you need to know:

* Element: Gold (Au)

* Atomic Number: 79

* Chemical Symbol: Au

* Appearance: Yellow, shiny, malleable, ductile, and highly unreactive metal.

So, the chemical composition of gold dust is simply Au.