Brilliant Chromatic Scale

Brillant Chromatic Scales are scales from Nefarius' chromatic dragonflight.

Source
This item drops from: in Upper Blackrock Spire, as well as Chromaggus in Blackwing Lair when skinned.
 * Chromatic Dragonspawn
 * Chromatic Elite Guard
 * Chromatic Whelp

Leatherworking

 * Chromatic Cloak

Trivia
It is possible the name is a pun on the musical chromatic scale.