This blue-black hair has double the blue: gun-metal blue in the base, and bright navy streaks in the top layer, all perfectly—and, ahem, expertly—blended together for a truly gorgeous finish.

Katy Perry has tried every hair color under the sun, from blue to pink to black and more. The singer has been dyeing her hair since she hit the music scene in the early 2000s. Believe it or not ...