*DISCLAIMER: THIS IS ALL JUST MY INTUITION AND OBVIOUSLY I HAVE NO FINAL SAY ON ANYTHING ELE-RELATED BUT THIS IS HOW I WOULD MAKE IT CONSISTENT WITH SCIENCE* Also sorry for long run-on sentences.
I think it would be advanced in the sense that it would likely take some familiarity with rocks and minerals and their structures and natures in order to have the idea that one was manipulating a single mineral. I sort of imagine that an eleven year old would just produce the rock that he was most familiar with, maybe one that occurred abundantly at home, probably something super generic like quartzite, every time he cast elemental spells; then maybe he'd be able to start differentiating between things like marble and sandstone because they look so different, but wouldn't be able to do this kind of stuff simply because he doesn't understand it. More familiarity with the nature of rocks and minerals would lead to a better understanding of crystal structure and composition that I think would probably allow them to do more with it, but if you didn't know something even existed, or if you didn't quite understand that a rock is made up of x y and z minerals, you'd never even conceive of trying to manipulate it and hence it wouldn't happen.
In my mind I imagine that once an elemental has mastered his element (you know, in the guide it always says after 50 or so they can just say Demin or Hor or Garth or whatever and make whatever they want/manipulate it however they like) they certainly possess the capability to single out and affect/create any mineral because they can affect/create any rock and this follows logically from that, and after that it would just depend on whether the elemental is even aware of this mineral or what this rock is made of, and if they are then they can start doing stuff with it. I bet some Demin acolytes spend a lot of time doing this kind of research. Most of the other elements barring earth are things that are super abundant and don't require this kind of understanding because they're things that humans have a great grasp on. Madin I would assume would also require this kind of understanding--you probably have to have at least some familiarity with a plant to create it (otherwise you could make extinct plants and screw over the ecosystem? idk maybe that is possible), so I imagine more effort goes into understanding/cataloging these things for scholars of those elements.
Of course, that's just kind of my rando thoughts on it. I was also thinking (but here I really am just making stuff up) that there may be constraints like is this substance a naturally abundant or hard to shape or hard to form thing? I imagine just due to hardness (diamond = 10, ruby/sapphire = 9, topaz = 8, something like quartz = 7, glass is at 5.5, going down to something like calcite (which makes up marble) = 3) that a lot of gems would take a lot more energy to manipulate that often crosses the line into not being worth it. It could be sort of a natural constraint against stone eles just making fantastical diamond sculptures in crazy shapes all the time or tons of giant diamond boulders (considering naturally on earth it's very difficult to get the temperature and pressure conditions to form it).
On the metal thing, I want to just say that due to aforementioned conflict with magic, the rule could just be that pure metals or alloys like brass can't be manipulated, while if there are metal ions in other substances the fact that they are somehow..."diluted" because there are other types of atoms in the molecule. That seems clearest to me. Maybe metallic rocks are also just harder to work with in general (think hematite (iron oxide), pyrite (fool's gold, iron sulfide), magnetite (another iron oxide)) due to the high presence of metal.
//idk idk someone else who knows science needs to help me
