Earthbound magic, it is widely known to the Wizards of the Colleges, has no inherent nature.
Earthbound magic, it is widely known to the Elementalists, inherits a nature from the material it resides within.
You spend a frustrating amount of time bouncing between these two seemingly irreconcilable facts. Earthbound magic is everywhere, and to your senses it is plain as day that it retains the same neutrality of nature wherever it resides. You skim through volume after volume searching for some explanation for why the Elementalists would pin their whole profession on something so plainly untrue, and you overlook the key to it all time and time again because of institutional ego. Time and time again you find it repeated within the books that Elementalists should avoid magical clashes with wielders of the Winds, and time and time again you react to it with only a smile. It's only in a treatise of an exceptionally boring Elementalist that you find the usually unwritten assumption actually written: that while Earthbound magic resonates within the material elements, it resonates much more strongly with the Winds that it originally was.
Of course you cannot see the elemental resonance within Earthbound magic - just by being in the same room as it, you have reverted it to its original nature. No experiment performed by a College Wizard, or performed within a College laboratory, will ever see anything but the neutral state of Earthbound magic. Come to think of it, anywhere in Altdorf would be subject to the same disruption, as for almost two centuries it has been constantly awash with the Wind of the current Supreme Patriarch. It is something like if you concluded that snow was a myth because you performed all your studies of it in the summer.
Having been slowly and agonizingly drawn to the conclusion that maybe the fundamental basis of Elementalism does exist, you return to the beginning and reread it with a slightly more open mind: Earthbound magic drawn from one of the four elements retains a resonance with that element, so it is more easily able to manipulate it. Earthbound magic drawn from water resonates with water, and thus can manipulate it more easily. Doing so to water that is itself also awash with Earthbound magic allows for the creation of Elementals, mobile accretions of that element able to perform simple tasks. By exploiting this resonance, and offloading some of the magical burden to energies already present within the manipulated element, the Elementalists are capable of magical feats far beyond what the raw power of the magic they're channelling would suggest.
It all makes sense. It is a very basic form, possibly the most basic form, of the conceptual resonance that Hedge Magic seems to rely upon. It explains why they are sometimes seen within the Elven quarter of Marienburg - because Elves do not transform themselves or their environment with a chosen Wind in the same way that College Wizards do, so they are able to identify and exploit the resonance for simple tasks when using Aqshy or Ghyran or Azyr would be overkill. Put that way, it slots neatly into the Cardinal understanding of the Winds that Elves prefer over the Elemental and Mystical understandings. Elemental in the Wind sense, that is - is even Reikspiel itself conspiring to confound the Colleges in this matter? Those two concepts have different words in Eltharin.
Might this, you cannot help but wonder, be part of the nature of Ice Magic? Ice in the Empire might be a transitory thing, but in Kislev it never entirely disappears, only withdraws to the mountains and glaciers. Could this permanence allow it to acquire a nature of its own for Earthbound magic to resonate with? If not on its own, then with the attentions of a God and the scavenged infrastructure of the Waystone network bent to this end?
With curiosity sated and institutional ego bruised, you return the books to the clutches of the Librarian-We and turn your attention back to your duties.