All items in Star Wars: The Old Republic have a quality or rarity rating associated with them, which is shown by the item's text and icon border color. The item quality indicates the item's worth and rarity. An item's level should also be considered as some higher level items with a lower quality can be better than lower level items of higher qualities. There are eight types qualities.
Cheap quality (Grey)
Items of this quality are among the most common mob drop and are mostly useless. They can be sold to a vendor for credits.
Standard quality (White)
Premium quality (Green)
Prototype quality (Blue)
Cartel Market Item(Orange)
Items of this color come from the Cartel Market and usually nowhere else.
Artifact quality (Purple)
Artifacts are high quality items. They can be found on corpses of flashpoint and operation bosses, as well as rare mission rewards or from crafting. These items are sometimes customizable. F2P players cannot use most Artifact quality equipment.
Legacy quality (Orange Yellow)
Items of this quality are part of the Legacy system of the game.
Mission quality (Yellow)
Items of this color are used for missions. They are either used or collected to fulfill mission objectives. They are stored in the Mission Items section of a player's inventory.