Stones of Barenziah

The Stones of Barenziah are an initially-scattered collection of twenty-four gemstones found in. Prior to appraisal, each Stone of Barenziah is labeled as "Unusual Gem". Once the first stone is found, there will be a miscellaneous objective that activates and indicates that the next step is appraisal. The city of Riften has two people capable of handling this task: Maul (an associate of Maven Black-Briar), and Vex, a member of the Thieves Guild.

After the appraisal, it is learned that a total of twenty-four Stones of Barenziah exist, which activates the quest No Stone Unturned. The stones are Quest items of 0.5 weight and worth 200 gold, which cannot be removed from the inventory until the entire set is obtained. Many of these stones can be found while completing small jobs for Vex and Delvin of the Thieves Guild.

No Stone Unturned quest


After handing in all twenty-four Stones of Barenziah, the Dragonborn is asked to recover the Crown of Barenziah from Tolvald's Cave.

Vex reveals that the Crown of Barenziah is an item that enhances a thief's ability. With the stones and crown in her possession, Vex says she can restore the paragon to its full strength.

Reward
Upon completion of the quest "No Stone Unturned" (by turning in all twenty-four stones and recovering the crown), Vex rewards the Dragonborn with the active effect and ability, Prowler's Profit. Furthermore, the fully restored Crown of Barenziah sits on a special stand in the cistern portion of the Thieves Guild.

Trivia

 * In recent patches the stones were made static, they no longer can be knocked off somewhere inaccessible when using explosive magic or walking over them. They cannot even be moved while pressing the interaction button. (PS3 and Xbox 360 Tested)
 * It is also possible to get the gem via the console command 'tcl'.
 * There is a way to get multiple gems from only one. Tap the interact button as fast as possible while targeting the stone. If done correctly, multiple stones may be picked up instead of one. Slow Time is a sure way to make use of the exploit. Any stones left over after finishing the quest will still be in their original locations. If picked up and dropped, they will hover in mid air, immobile. They may be picked up again, and can be stored or sold.
 * Until the stones are appraised by Vex, they stack. After the quest begins, each new stone will take a new inventory line. (Confirmed for 360, PS3 and PC)
 * The Stones have a marked value of 200 but stealing one while on a Bedlam job for the hold it is located in will complete the quest objective.