For Mega Stone locations in OR/AS, click here! You can find all of the old Mega Stones in OR/AS too. If you want Mega Stones in X and Y, see below
Note that most of the Mega Stones require your Mega Ring to be upgraded to appear. To upgrade your Mega Ring, you must firstly defeat your rival in Kiloude City. He or she will be at the pond at the top of the town if you use the Battle Maison for a while. Then, meet Prof. Sycamore in Anistar City's sundial and he will upgrade your Mega Ring.
Abomasite
This one is given to you if you talk to the Abomasnow you saved at the end of Frost Cavern.
Absolite
If you defeat your rival in a battle in Kiloude City (which is postgame), he or she will give you their spare Absolite.
Aerodactylite
A scientist in the Fossil Lab in Ambrette Town will give it to you once you have returned from the Glittering Cave.
Aggronite
Requires an upgraded Mega Ring
This one can only be found from 8 - 9 PM and is exclusive to Y. When you enter Cyllage Gym, go to the right and climb the first wall, then climb the next wall on the right. It is on the ground around the corner.
Alakazite
Requires an upgraded Mega Ring
This one can only be found from 8 - 9 PM. You can find this Mega Stone on B3F of the Reflecting Cave.
Ampharosite
Go to Azure Bay and you'll find an old man on an island who will give this to you. The man is standing next to a fisherman and the island is just south of the Sea Spirits Den entrance.
Banettite
Requires an upgraded Mega Ring
This one can only be found from 8 - 9 PM. It can be found at the Chamber of Emptiness, which can be accessed via Route 22.
Blastoisenite
When you get to choose one of the former starter Pokemon from Professor Sycamore, pick Squirtle and you'll get this Mega Stone. If you didn't get it from him, you will be able to buy it from a man in the Stone Emporium in Lumiose City. It costs 1,000,000 - 10,000 Pokedollars depending on how stylish you are and is only available every three days.
Blazikenite
You get this from the event Torchic that is being distributed via Mystery Gift until January 2014. You need to go to the main menu and choose Mystery Gift. Select Receive Gift, then Via Internet and you'll get the Torchic after visiting talking to the woman to the left of the desk in any Pokemon Center. It's holding the Blazikenite. You cannot get this Mega Stone otherwise.
Charizardite X/Y
When you get to choose one of the former starter Pokemon from Professor Sycamore, pick Charmander and you'll get this Mega Stone. Depending on the version of the game you have, you'll receive either the X or Y version of the stone. If you didn't get it from him, you will be able to buy it from a man in the Stone Emporium in Lumiose City. It costs 1,000,000 - 10,000 Pokedollars depending on how stylish you are and is only available every three days.
Garchompite
Requires an upgraded Mega Ring
This one can only be found from 8 - 9 PM. You'll find this one near a small tower loward the latter end of Victory Road. The tower is behind a wall that must be destroyed by Rock Smash.
Gardevoirite
Find Diantha in Lumiose City, who is in Cafe Soleil (ride a Lumi Cab to find it easily). Trade any Pokemon with her to get a Ralts with the stone. This is only available postgame.
Gengarite
A Hex Maniac will give this to you in Laverre City.
Gyaradosite
Requires an upgraded Mega Ring
This one can only be found from 8 - 9 PM. It's in the south-eastern section of Couriway Town. There are three small waterfalls and this stone is in the middle one.
Heracronite
Requires an upgraded Mega Ring
This one can only be found from 8 - 9 PM and is exclusive to Pokemon Y. It's found in some tall grass in Santalune Forest, near the Route 2 entrance.
Houndoominite
Requires an upgraded Mega Ring
This one can only be found from 8 - 9 PM and is exclusive to Pokemon Y. In Route 16, there is a spot where two skaters are going around a rock formation. The stone is on the ground on the southern side.
Kangaskhanite
Requires an upgraded Mega Ring
This one can only be found from 8 - 9 PM. Go inside Glittering Cave and take the first right. The stone will be found at the dead end.
Lucarionite
After defeating Korrina at the Tower of Mastery, she'll give you a Lucario holding this.
Manectite
Requires an upgraded Mega Ring
This one can only be found from 8 - 9 PM and is exclusive to Pokemon X. In Route 16, there is a spot where two skaters are going around a rock formation. The stone is on the ground on the southern side.
Mawilite
Requires an upgraded Mega Ring
This one can only be found from 8 - 9 PM. When you enter Shabboneau Castle at Camphrier Town, go to the left and use the stairs to get to the second floor. The stone is on the ground just north of the western staircase.
Medicahnite
Requires an upgraded Mega Ring
This one can only be found from 8 - 9 PM. It can be found in Lavarre City, by a well.
Mewtwonite X/Y
The stone you receive depends on the version of the game you have. You'll get the stone when you capture Mewtwo in the cave west of Pokemon Village.
Pinsirite
Requires an upgraded Mega Ring
This one can only be found from 8 - 9 PM and is exclusive to Pokemon X. It's found in some tall grass in Santalune Forest, near the Route 2 exit/entrance.
Scizorite
Requires an upgraded Mega Ring
This one can only be found from 8 - 9 PM. It can be found behind the Abomasnow at the end of Frost Cavern.
Tyranitarite
Requires an upgraded Mega Ring
This one can only be found from 8 - 9 PM and is exclusive to Pokemon X. When you enter Cyllage Gym, go to the right and climb the first wall, then climb the next wall on the right. It is on the ground around the corner.
Venusaurite
When you get to choose one of the former starter Pokemon from Professor Sycamore, pick Ivysaur and you'll get this Mega Stone. If you didn't get it from him, you will be able to buy it from a man in the Stone Emporium in Lumiose City in the postgame. It costs 1,000,000 - 10,000 Pokedollars depending on how stylish you are and is only available every three days.
