In video gaming, Item quality is a way of determining, usually by color-coding, the "rarity" or "power" of a given item or piece of gear. In tabletop gaming, this is usually accomplished by using a suffix like +n, where n is a numerical figure; video games, because of their general nature of being interface-driven, will often use color to denote such power, although this doesn't hold true for every game. The most common video games where item quality is used are MMOs, where different quality tiers can be found across this genre.
Usually represented by a light grey color, these items are inferior pieces of equipment, and usually only fit to be sold to a vendor for currency.
Common is the standard item quality, usually represented by white.
These items, sometimes represented by a light green color, are slightly-above-average quality items, providing a modest boost in stats over common-quality items.
Also known as Superior, this quality of item provides superior stats over an Uncommon-quality item of the same type. This item is typically colored blue.
Epic items, typically colored purple, normally signify the highest item quality possible through normal gameplay, and typically provide superior stats over Rare-quality items of the same type.
Legendary items, typically colored orange, usually represent a reward after a significant time investment in a quest chain, and often provide the highest stats for their gear type.
Artifacts, with color varying by game from light gold, to purple, to orange, are typically specific items tied to a race or class. Artifacts may also be called Relics.
Typically found in World of Warcraft and colored light blue, these items are used to provide experience and stat boosts to low-level characters while they participate in the levelling system.