So what are the colors of metal?
If this is a general question, it'd be hard to answer. Though most metal songs seem to have black in it, I'm not sure why.
Pentagram - Sign Of The Wolf
Black and gray. The vocals are a really dark green.
Manilla Road - Necropolis
Dark gray, the chorus having some streaks of yellow in it, kind of like a sunrise.
Judas Priest - Beyond The Realms Of Death
This is an odd one. Usually I get lighter colors with B minor, but it's mostly red, black, with a blue undertone once the distorted guitars come in. The colors also seem a bit empty, if that makes sense. On an unrelated note, I love this song.
Candlemass - Black Stone Weilder
Yellow, black, and green.