The Exquisite Sapphire is a unique miscellaneous item added by The Elder Scrolls V: Dragonborn. It appears to be of a lighter blue and to be quite shinier than a regular sapphire.
Background[]
Sapphire tells the Dragonborn that she always carried around this sapphire for good luck.
Acquisition[]
Obtained by bringing Glover's Letter to Sapphire.
Glover's Letter respawns every seven to eight in-game days, allowing the letter to be given repeatedly and the sapphire infinitely acquired.
Usefulness[]
It is the single most expensive miscellaneous item in The Elder Scrolls V: Skyrim, and has the highest value to weight ratio in the game, not counting items with zero weight such as gold.