Nintendo and Game Freak introduced Mega Stones to the Pokémon universe in X and Y for 3DS, granting a handful of Pokémon stronger abilities. These precious collectibles return in Omega Ruby and Alpha Sapphire, with over 40 to find in the Hoenn Region. Once you have a Mega Stone, you’re able to Mega Evolve one Pokémon per battle. 

A Mega Stone is nearby if you see sparkles on the ground. From there, walk over and press the A button to collect it. Of course with an area as big as Hoenn, finding each one of these things is easier said than done. To make things simpler, we have this Mega Stone location guide. 

Mega Stones that appear in the beginning

Mega Stone Location Info
Absolite Safari Zone Look for it in the area.
Aggronite Rusturf Tunnel Receive it for breaking rocks with Rock Smash.
Alakazite Slateport City You will find this in the market.
Altarianite Lilycove City Bring an Altaria to Lisia's fan.
Banettite Mt. Pyre It's at the summit.
Beedrillite Sea Mauville You'll find it in Storage.
Blazikenite Route 120 or Route 114 Steven gives it to you on Route 120 if you have Torchic. If you don't, buy it on Route 114 after taking down the Super Ancient Pokemon
Garchompite Fortree City Aarune presents it to you once your team achieves Platinum Rank at the Secret Base Guild.
Glalitite Shoal Cave Look for it in the ice cavern.
Gyaradosite Route 123 All you need to do is scratch Poochyena in 123 Go Fish.
Heracronite Route 127 It's on an island.
Latiasite Southern Island You'll get this one via story events.
Latiosite Southern Island You'll also get it through story events.
Lucarionite Any contest hall Defeat Lisia in a Master Rank event.
Manectite Route 110 It's located near Cycling Road.
Mawilite Verdanturf Town You'll discover this one on the ground.
Medichamite Mt. Pyre It's in the area... somewhere.
Pidgeotite Verdanturf Town First, locate Shroomish for the girl in Verdanturf Town. From there, show the stone she gives you to Mr. Stone in Rustboro City.
Pinsirite Route 124 It's on the ground.
Sablenite Sootopolis City This one is near a bridge by Cave of Origin.
Sceptilite Route 120 or Route 114 Steven hands it over on Route 120 if you have Treecko. If not, take out the super ancient Pokemon and buy it from the seller on Route 114.
Slowbronite Shoal Cave Receive the Shell Bell from the old man.
Steelixite Granite Cave Look on the lower levels.
Swampertite Route 120 or Route 114 Steven gives it to you on Route 120 if you have Mudkip. If you don't, buy it on Route 114 after taking down the Super Ancient Pokemon

Mega Stones that appear after taking down super-ancient Pokémon 

Mega Stone Location Info
Abomasite Route 123 Look in Berry fields.
Aerodactylite Meteor Falls It's on the ground.
Ampharosite New Mauville It's on the ground.
Charizardite X Fiery Path It's on the ground.
Charizardite Y Scorched Slab It's on the ground.
Gardevoirite Verdanturf Town Go to Wanda's home and speak with her.
Houndoominite Lavaridge Town It's on the ground.
Kangaskhanite Pacifidlog Town It's on the ground.
Lopunnite Mauville City Go to Mauville Hills and talk to the businessman.
Mewtwonite X Littleroot Town It's on the ground.
Mewtwonite Y Pokemon League It's on the ground.
Scizorite Petalburg Woods It's on the ground.
Tyranitarite Jagged Pass It's on the ground.
Venusaurite Route 119 It's on the ground.
Red Orb Sootopolis City You'll get this via story events.
Blue Orb Sootopolis City You'll get this via story events.

Mega Stones that appear during or after the Delta Episode

Mega Stone Location Info
Audinite Battle Resort Speak with Looker while at the Battle Resort.
Blastoisinite S.S. Tidal It's on the ground.
Cameruptite Team Magma's Hideout of the Battle Resort You'll receive it during the Delta Episode, or a Team Magma Grunt will give it to you at the Battle Resort.
Galladite Fallarbor Town Speak with Professor Cozmo at his laboratory.
Gengarite Battle Resort It's on the ground.
Latiasite Littleroot Town Speak to your mom while at your house.
Latiosite Littleroot Town Speak to your mom while at your house.
Metagrossite Pokemon League Beat Steven again.
Salamencite Meteor Falls Chat with the old women.
Sharpedonite At the Battle Resort or Team Aqua's Hideout A Team Aqua Grunt will give it to you at the Battle Resort, or you'll receive it during a Delta Episode.

Mega Stones you’ll find in other ways

Mega Stone Location Info
Diancite n/a Distribute Diancie through previous special events in your party, then visit a Pokemon Center. 

Now you'll have all of the Mega Stones in Pokemon Omega Ruby and Alpha Sapphire.