Mega Stone Locations

A Mega Stone is a held item which allows certain Pokémon to mega evolve. It is only usable if the player has acquired the Mega Ring from the Mega-Z Ring Sidequest.
In Pokémon Reborn, they appear as grey Pokéballs on the ground which can be picked up but can also be given to the player by NPCs.
Mega Stone 	Available 	Location 	Guide
Ampharosite 	After Badge 08	The Underroot 	Guide
Aerodactylite 	After Badge 10	Route 2 	Guide
Charizardite X	After Badge 11	Calcenon City 	Guide
Banettite 	After Badge 11	Ametrine City 	Guide
Abomasite 	After Badge 12	Ametrine Mountain 	Guide
Audinite 	After Badge 13	Azurine Cave 	Guide
Altarianite 	After Badge 13	Azurine Lake 	Guide
Beedrillite 	After Badge 13	Azurine Lake 	Guide
Glalitite 	After Badge 13	Azurine Lake 	Guide
Blastoisinite 	After Badge 13	The Underroot 	Guide
Cameruptite 	After Badge 13	Chrysolia Spring 	Guide
Sharpedonite 	After Badge 13	North Aventurine Woods	Guide
Venusaurite 	After Badge 13	Lower Peridot Ward 	Guide
Lopunnite 	After Badge 14	Grand Hall 	Guide
Steelixite 	After Badge 14	Devon Corp 	Guide
Aggronite 	After Badge 14	Underground Railnet 	Guide
Medichamite 	After Badge 14	Sugiline Cave 	Guide
Mawilite 	After Badge 14	Teknite Ridge 	Guide
Pidgeotite 	After Badge 14	Teknite Ridge 	Guide
Houndoominite 	After Badge 14	1R253 Scrapyard 	Guide
Slowbronite 	After Badge 15	Fiore Arena 	Guide
Absolite 	After Badge 16	Grand Hall 	Guide
Garchompite 	After Badge 16	Grand Hall 	Guide
Kangaskhanite 	After Badge 16	Tanzan Depths 	Guide
Heracronite 	After Badge 16	Charous Mountain 	Guide
Gyaradosite 	After Badge 16	Glass Workstation 	Guide
Sablenite 	After Badge 16	Glass Workstation 	Guide
Manectite 	After Badge 16	Agate City 	Guide
Pinsirite 	After Badge 16	Agate City 	Guide
Galladite 	After Badge 16	Agate City 	Guide
Scizorite 	After Badge 16	Agate City 	Guide
Blazikenite 	After Badge 16	Agate City 	Guide
Gardevoirite 	After Badge 16	Devon Corp? 	Guide
Sceptilite 	After Badge 16	Route 4 	Guide
Swampertite 	After Badge 17	Labradorra City 	Guide
Alakazite 	After Badge 17	Dr. Connal's Orphanage	Guide
Charizardite Y	After Badge 17	Calcenon City 	Guide
Tyranitarite 	After Badge 18	Victory Road 	Guide
Gengarite 	After Badge 18	Victory Road 	Guide
Lucarionite 	After Badge 18	Victory Road 	Guide
Salamencite 	After Badge 18	Victory Road 	Guide
Metagrossite 	After Badge 18	Charous Path 	Guide
Latiasite 	During Tier 6 	Mirage Tower? 	Guide
Latiosite 	During Tier 6 	Mirage Tower? 	Guide
Diancite 	During Tier 7 	Rhodochrine Tree 	Guide
Mewtwonite X 	During Tier 7 	Calcenon City 	Guide
Mewtwonite Y 	During Tier 7 	Calcenon City 	Guide