(#NOT BY ME#)
After the cut you'll find all 24 Stones of Barenziah locations in Skyrim.
Search the Hall of the Dead in Whiterun. In the first room of the Catacombs on the left wall near a skeleton you'll find a stone.
Search the Jorrvaskr in Whiterun, you'll find a stone in Kodlak’s room.
In the House of Clan Shattershield in Windhelm, you'll find the stone in the first upstairs bedroom to your left.
North of Ansilvund and southeast of Windhelm you'll find a cave called Stony Creek Cave. You'll find the stone in the Bandit Wizard's cavern.
In the Palace of Kings in Windhelm, you'll find the stone on the table in Wuunferth the Unliving’s Quarters.
On the Dainty Sload, a boat in Solitude between the Lighthouse and Solitude check out the Captain’s Quarters. You'll find the stone on the table.
If you purchase Proudspire Manor in Solitude for 25,000 gold after gaining the Jarl's trust, you'll find a stone in the master bedroom.
In the Blue Palace in Solitudue check in the Jarl Elisif's quarters. You'll find the stone on one of his shelves.
In Yngvild, a cave north of Winterhold and east of Dawnstar, check behind the throne to find a chamber that is hiding the stone.
In the College of Winterhold during the Under Saarthal quest search the shelves of the Arch-Mage’s Quarters to find a stone.
In Hob’s Fall Cave, a cave in the area between Dawnstar and Winterhold, you'll find the stone near the necromancer's sleeping area by the alchemy lab.
In the Treasury House in Markarth find the stone next to bed in the master bedroom.
In Understone Keep in Markarth, look for a locked door to a side room of the Dwemer Museum. You'll find the stone in the room on a table.
Southwest of Markarth, you'll find Dead Crone Rock. In front of the Word Wall at the top there will be an altar, you'll find the stone on the altar.
Inside the Dark Brotherhood Sanctuary, check in Astrid’s room. You'll find the stone on a dresser.
In Thalmor’s Embassy, while on (or after you've completed) the quest “Diplomatic Immunity” for Delphine,check in Elenwen’s Solar. You'll find the stone in a bedroom.
In Dragonsreach in Whiterun, check the Jarl’s bedroom to find the stone.
East-northeast of Whiterun you'll find a dungeon called Fellglow Keep. You'll find the stone on the counter of the workroom at the top of the front foyer.
Northeast of Rorikstead and southeast of Marthal you’ll find a dungeon called Rannveig’s Fast. You'll find the stone on a table near the prison area.
In Ansilvund a tomb in Eastmarch, you'll find a stone in the burial chambers near where you encounter Fjori's ghost.
In Mistveil Keep in Riften find the stone in the Jarl's Quarters.
East of Riften in the Black Briar Lodge you'll find the stone upstairs in the master bedroom. Note: Black Briar Lodge is different than Blackbriar Manor, so don't confuse the two.
Northeast of Falkreath you'll find a farm called Pinewatch. Inside the farmhouse, you'll find a secret entrance to the Bandit Sanctuary. Go there and make your way towards a room with empty draugr tombs. Once there you'll find a locked door directly to your right. Use a lockpick on the door and you'll find the stone on the top shelf of the a bookcase.
South of Gjukar’s Monument and north of Moss Mother Cavern, in Falkreath, you'll find Sunderstone Gorge. Inside, stone on an altar in front of a Word Wall.
Once you've found all 24 Stones of Barenziah, Vex from the Thieves Guild will ask you to recover the Crown of Barenziah from Tovald's Cave. According to the Vex, once you recover the crown, which is a paragon for the Thieves Guild, she'll be able to restore it to its full strength and reward you with the Prowler's Profit.