Too thin oxide layer looks light, up to the color of metallic copper.

There's a bit of very finely divided metallic copper there too, God knows why.

A nice, thick cloud of hot ionized metallic copper.

This involved heating zinc ore and charcoal with metallic copper in a closed vessel to about 1000 C.

Pure metallic copper produces a very dark red, opaque glass.

"We got every last bit of metallic copper in the whole city," the foreman said, proudly.

Of course, it looks nothing like good old metallic copper, which bothers my students (and, I admit, me) to no end.

With pink-tinged lips, like metallic copper in a silver face, it said: "Who is this one?"

Two possibilities come to mind: One possibility is that the metallic copper serves as one electrode.

At the cathode, the Cu is reduced to metallic copper by gaining two electrons.