Copper powder is a rusty orange colored fine powder which was used not so long ago in the manufacture of stars to achieve a green and blue colors. Atomized powder is particularly well suited to the strobe applications. It is no longer used today as it is replaced with chemicals like barium and copper oxides.
Copper powder can be purchased through craft or ceramic stores.
The metal, when powdered, is a fire hazard.
At concentrations higher than 1 mg/L, copper can stain clothes and items washed in water.