Mega Stones

Megas found in the wild:
Metagrossite - Axe tree/Crystal Cave

Gengarite/Banetite - Mansion

Gyaradosite - in the water dimension

Galladite/Gardevoirite - Near Axe Tree

Lopunnite - Axe Tree

Sablenite - Unown Shrine in Underground Lab

Blazikenite - Around Volcano

Altarianite - Acid, where Zapdos and Thundurus spawn

Mega Stones Available in the shop only:
Venasaurite - $1000 poke-dollars

Charizardenite X/Y - every where

Blastoisinite - $1000 poke-dollars
Slowbronite - $1250 poke-dollars

Mega Stones coming soon (MU and Tournaments) :
Beedrillnite - Spawnable in swamp

Mewtwonite Y - Tournament prize

Latiasite - Tournament prize

Latiosite - Tournament prize

Diancite - Tournament prize

Mega(s) given from Uglypoe:
<p style="font-weight:normal;font-size:16px;">Mewtwonite Y - Champion ranking and all Normal Pokemon maxed out and maxed out shinies.