A Quest Item is an item that is related to a quest.
Often, the objective of the quest involving the quest item is simply to collect a specified number of the named item.
Quest Items have their name displayed in bold blue and have no Trade Value.
Quest items cannot be sold as they have no Trade Value. They will take up a slot in your inventory until you complete the quest, drop or destroy them.
For a detailed list of Quest Items see Category:Quest Items.
Quest Items are not to be confused with regular Drops which are also subject to some quests.