why does Cu (s) produced in a redox reaction look different from copper metal piece?

Answer 1

The English in your question is a little bit difficult to understand. But from what I gather you may be asking about the differences in the look of copper.

When copper oxidizes over time it changes to a greenish tint.
Most of us associate copper with a brownish type color; but as many metals do the color does change. Maybe that answers your question. I am not sure what copper metal piece you are speaking of.

Answer 2

Nobody answered "why" so I'll give it a shot. Changing the electron configuration of an element, such as copper undergoing redox greatly changes the absorption and reflection properties of the element. And since color is merely the totality of absorption and reflection properties of a substance, it follows that altering this will alter the perceived color.

Answer 3

When Cu(s) results from a smelting operation, the result is shiny red metal. When Cu(0) results from a redox reaction in water solution, it is a black powder. The blue-green color that develops on copper metal is basic copper salts of cupric [Cu(II)] and not copper itself.