Magic Stuff

You can't just call it "magic stuff," there are official names.
Like what? There are so many different names and no one agrees because it's never been much of a thing here.
I don't know. Pick one that sounds good.
I'll call it what I want, thank you. There's too many names and a surprising number of copyrights involved. Besides, you know someone will get offended if I somehow forget their exact use case. "Stuff" is fine.
Somewhere out there is an eldritch being shaking its head in dismay.
Let it shake. It's "stuff."

— Evelyn Suthmeer and Ruby Gray 

This world does, on occasion, possess what might be termed as actual literal magic. Magic in a World of Science is a difficult thing to figure out here, since it's not terribly common. The main factor is that the "magic stuff" isn't a normal part of our life here on Earth. It is, however, a quantifiable thing that can help us measure how to use magic here on our planet.
E/N: She wants to try necromancy, but fortunately that's not all that feasible even in places with a lot of...magic stuff.
I have a purely academic interest in this since I have my own superpowers and thus don't have a particular need to use magic. So there.

Properties

Material Characteristics

I don't think it has any physical characteristics. At least, not in this dimension. There's probably some magic dimension out there where it's tiny floating balls of light or puffs of smoke, but in our reality there are no signs determinable by the usual five senses.
It is something, though. Most of the readings I get show it as a sort of radiation, so most of the observable points are the thing the magic stuff is clinging to. Like how a toy or a building could be radioactive.

Origin & Source

If it has an origin point, this information is closely guarded and should remain so. Finding a source of power for "the thing that gives us all the superpowers albeit temporarily and with less oomph" would probably be a disaster for everyone, universally.

Type

Elemental / Molecular