I'm new to all this Mage stuff, never really played as one before in any Elder Scrolls game. Is this the best stone to have as a pure mage? I'm specialising in Illusion and Conjuration if that makes a difference?

Nonono, if you are a true mage (not anti-mage) you will go the apprentice stone, twice as fast magicka generation but twice as much damage taken from spells (resistances are broken so it might not be twice but way less)

Yeah that's the first thing I did after the tutorial. But I'm at a level where I'm happy and not that bothered about leveling quickly. I just wanna get the best out of using my spells.

EDIT: Scrap that, I read that wrong I got the Mage Stone not the Apprentice. Also I'm a Breton so I have a good magic resistance anyway.

A bug exists that stops most of the conjuration spells working with the atronach stone. I wouldn't bother as the best conjuration spells are affected. Its the same with the alteration perk 'atronach'.

apprentice stone isn't as good for pure destruction mages, but very good for conjuration (pet tanking) and illusion, where you can "disable" enemy mages before they hit you

When you find the different stones experiment and find which one works best for you.

"Skyrim" and the "Elder Scrolls" series in general flies in the face of convention by not having "perfec builds".

Something many gamers struggle to accept.

Azrael
The Nord with the Sword

Ah, that's good to know also.

EDIT: I'll think I'll go for the Apprentice Stone if it benefits Illusion and Conjuration.

However earlier on there probably would be less mage encounters and more bandit encounters, lol. Anyway you might want to try out the Lord stone, gives 50 pts damage resistance and 25% magic resistance, quite good for later levels. I personally find the apprentice stone to be kinda weak, 100% decreased magic resistance aint no small matter

Apart from the conjuration issues the Atronach stone is the strongest defensive stone imo, for everyone really.

Casting a summon six times to get it to work can see you dead, but absorbing 6 fireballs in a row might make up for that, just perhaps not if conjuration focused.

Once you get good self-enchanted gear the 50% mana regen is no longer an issue.

Otherwise I would probably just get The Lord Stone, 25% magic resist and 50 armour.

Not sure I agree, even ignoring the fact that magicka regeneration +100% isn't the same as twice as fast magicka regeneration (consider that other magicka regeneration effects maybe at play), the fact it slows down so much in battle kinda makes it pointless. If not for a bug related to absorb spell, then the Atronach Stone would be the best for mage since +50 magicka really does more for combat then 150 magicka regeneration speed does, tho 150 magicka regeneration speed is relative (if you're say using archmage's robes and have regeneration perks from the restoration school you'll notice barely any difference, if you have no other regeneration effects you'll notice it a lot outside of battle). The bug however is the killer, it randomly absorbs some self-cast spells like conjuration which doesn't at all help, as such given that the apprentice stone effectively makes you a sheet of paper against any other mage I've stuck to the mage stone and will later probably go lord's stone when mage stone isn't needed anymore.