Made by the Formari, these lyrium-infused rings are supposed to help apprentices retain their lessons. They work rather well--too well, perhaps, as less-capable students sometimes wear three or four per finger. This ring boosts experience points by 1%.
Because the game will always round fractions down, this item provides no additional experience on gains of less than 100 points.
By the time you get to level 24 a 1% increase in XP would result in an extra 1725 XP, enough to get you 12.7% of the way to level 25 (less, actually, because this calculation doesn't account for the loss of XP to the above mentioned rounding error), but not worth tying up one of your ring slots for the entire game.
This item was originally only available to players who pre-ordered a copy of Dragon Age: Origins from any retailer.