How much Petricite is in Demacian architecture nowadays?

Given the similarities between Galio's stonework and just about every piece of Demacian architecture we've seen...

http://universe-meeps.leagueoflegends.com/v1/assets/images/factions/image-gallery/demacia-silvermere.jpg

http://universe-meeps.leagueoflegends.com/v1/assets/images/factions/image-gallery/demacia-citadel.jpg

http://universe-meeps.leagueoflegends.com/v1/assets/images/factions/image-gallery/demacia-hallvalor.jpg

http://universe-meeps.leagueoflegends.com/v1/assets/images/factions/image-gallery/demacia-templelightbringers.jpg

http://universe-meeps.leagueoflegends.com/v1/assets/images/factions/image-gallery/demacia-grandplaza.jpg

...A fucking lot of it.

We don't really know the size of this great petrified forest, but if there's enough to make Galio and as much architecture as Demacia has, then it either speaks to:

A: Demacia's great at being efficient with that woof with the lime and ash.

B: The forest is fucking enormous.

I imagine less is needed in tbe interior regions, while the outer walls have enough to stop undead juggernauts kept alive by magic from smashing through like a battering ram.

Which is probably why Demacia plays the defense game more than any nation off the top of my head save Ionia.

Well, the old lore featured a College of Magic in Demacia. At one point, Lux ran to her home to show off something to her parents, implying the college was near enough for her to only worry about being marked absent.

But... I think these things could and should be retconned. I'm not saying we need to get DragonAge here with an order dedicated to killing mages if they step out of line, but I could see a College of Magic being somewhere remote in Demacian territory where they could practice their skills without terrifying the common populace.

Given the weirdness of Runeterra and the fact that there is a ton of that white anti-magic cement everywhere in Demacia, I get the uncanny feeling that the stone trees grow back just like normal trees.

Also: Maybe what makes Lux so special is the fact that she can cast magic in spite of the anti-magic rock?

{quoted}

Cause if there's still a lot, I can't imagine how Lux could ever cast spells.

Note that there seem to be different SORTS of magic in Runeterra. It's possible that the darker, more malevolent magic we see in characters from Noxus is fundamentally different from that wielded by, say, Lux or Bard or Brand. I imagine Brand unleashed on Demacia would still be devastating, for example, and I can't imagine Bard's magic being stopped by stone from a mortal realm.

So it may just be that Lux--and many other characters--wield a force that isn't exactly the same as the force some other mages wield. "Magic" is a catch-all term, but, like anything else, it has MANY varieties.

Since Demacia is a little weary of magic, I could see them trying to suppress Lux's power which could already be enough to still show with all the petricite buildings around. So maybe her armor is made to further dampen her abilities. Not that it necessarily works very well.

There are two option why Lux still has the ability to cast spells.

1. Lux has such a high magic potential/power that even surrounded by such much Petricite doesn't affect her magic.

Or

2. Lux has a resistance against Petricite. It would makes sense - Demacia trust their anti-magic stone so much, they would never get the idea, that the mages could evolve a immunity against it. I mean, this lies in the realm of possibility. Just look at all this antibiotic-resistant bacteria we are breeding...