Pure copper is hard if not impossible to come by but copper tends to be reddish or pinkish in color. Annealing tends to change this color a bit too. Copper mixed with tin, silver, lead, zinc(the popular copper alloys) added it tends to look more of the color brass with bronze a bit darker. There is one copper alloy that tends to look almost purple in color.
Here's a
link that might help out. With so many alloys, it's hard to tell exactly by look without getting scientific.