Every item in Heroes vs. Monsters has a quality rating. The quality is displayed by the color of an item. Below is an example of the quality of different items:
[Greaves] - Poor (Grey)
[Shooter Cloak] - Common (White)
[Disciple Robe] - Rare (Green)
[Blade of Courage] - Superior (Blue)
[Iron Fist] - Epic (Purple)
[Dagger of Stars] - Godlike (Orange)
[Truesilver Blade] - Legendary (Gold)