You cannot find the Mega Stone for Latios in Pokémon X or Pokémon Y.
Mega Charizard X, which is exclusively for Pokémon X, is a Fire/Dragon-type Pokémon, while Mega Charizard Y is Fire/Flying (Pokémon Y only).Its respective Mega Stone is acquired as soon you pick Charmander from Professor Sycamore.
There is no such thing as a mega stone in Pokémon Pearl. Mega stones were first introduced in Pokémon X and Y and are required for certain Pokémon to Mega Evolve, which is a temporary new evolution stage.
In Pokémon X and Y, the Chamber of Emptiness is where you can find the Banettite, which is the Mega Stone for Banette, and the Spooky Plate for Arceus.
In Pokémon X and Y, the Intriguing Stone can be traded to a Hiker in Shalour City in exchange for a Sun Stone. In Omega Ruby and Alpha Sapphire, the Intriguing Stone can be brought to Mr. Stone, who will give you a Pidgeotite. This will allow you to mega-evolve Pidgeot.
That's unknown. Arceus is already too strong as it is now, it doesn't need a Mega Evolution, and holding a Mega Stone would prevent the use of the Multitype plates anyway.
In Pokemon X and Y you are not allowed to sell mega stones unfortunately. They are considered a special item.
MEWTWO is a very strong Pokemon with the 2nd highest sp atk in the game!!! Its speed is good aswell!! In the Pokemon first movie mewtwo is enemy and against mew but mew beat him so they are both good.
This depends if you are referring to Mega Charizard X or Mega Charizard Y. Mega Charizard X is black and blue with darker blue wings. Mega Charizard Y has similar coloring to regular Charizard and is orange and yellow with turquoise wings.
Good physical sweepers in Pokemon X and Y are Mega Lucario, Mega Mawile, and Heracross. Other good special sweepers in Pokemon X and Y are Manectric, Alakazam, and Mega Gengar.
Mewtwo can Mega Evolve into either Mega Mewtwo Y or Mega Mewtwo X.
Charizard is not capable of naturally evolving further however as of Pokémon X and Pokémon Y, Charizard is capable of mega evolving into Charizard X or Charizard Y. Your trainer will need the Mega Ring in Pokémon X or Pokémon Y and then Charizard will need to be holding one of its respective Mega Stones in order to receive the option to mega evolve.
The Pokémon confirmed to have a Mega Evolutionin Pokémon X and Y are the following:Generation IPinsir - Bug/FlyingAlakazam - PsychicGyarados - Water/DarkGengar - Ghost/PoisonAerodactyl - Rock/FlyingKangaskhan - NormalVenusaur - Grass/PoisonBlastoise - WaterCharizard X - Fire/Dragon (Pokémon X exclusive)Charizard Y - Fire/Flying (Pokémon Y exclusive)Mewtwo X - Psychic/Fighting (Pokémon X exclusive)Mewtwo Y - Psychic (Pokémon Y exclusive)Generation IIAmpharos - Electric/DragonHeracross - BugScizor - Bug/SteelHoundoom - Dark/FireTyranitar - Rock/DarkGeneration IIIBlaziken - Fire/FightingMawile - Steel/FairyAbsol - DarkGardevoir - Psychic/FairyMedicham - Fighting/PsychicAggron - SteelBanette - GhostManectric - ElectricGeneration IVLucario - Fighting/SteelGarchomp - Dragon/GroundAbomasnow - Grass/IceWhen a Pokémon is in this state, the prefix Mega is added to their names (e.g., Mega Blaziken).