[header] How to get diamond camo in black ops 2 [title] Unlock all the weapons on a particular class. [step] Play through the game and make sure that all weapons in a specific class have been unlocked and are available to use. [substeps] Weapons can be unlocked only when your character reaches a certain level (such as the r870 mcs, which can be used when your character reaches level 4). 
Complete missions and battle out on multiplayer matches to keep gaining experience points (xp) to raise your character's level a lot quicker. [title] Unlock gold camouflage for every weapon in a particular class.