Hehe, nice avatar Lantarion

.
I'm going to write a crazy notion of mine here. I don't remember seeing it explicitly stated anywhere.
Think of the instances of "good magic" (not
Sauron's or
Saruman's devices) in the books. Let's focus on the
Hobbit and LotR.
The Hobbit:
Thorin's
map (and the writing that could be seen by moonlight)
The Enchanted River in
Mirkwood
Erebor's hidden door
Gandalf tricks with fire
FotR:
Elrond commanding the Bruinen
Healing?
Gandalf tricks with fire
Orc-detecting
swords
The
Doors of Durin
The shutting spell
The "
Lórien effect"
The Mirror of
Galadriel
After FotR Gandalf
the White is around, with his power 'unveiled', and we don't see much new 'veiled magic'.
Now let's filter out the "rings influence". The Mirror of Galadriel, and possibly the "Lórien effect" (time stopping), are due to Galadriel's ring; Gandalf tricks with fire to his ring; and Elrond's command of the Bruinen to his ring. (I think).
We're left with the work of
craftsmen,
dwarves and
elves (doors and swords), and perhaps Elrond's skill with healing, though I would not really ascribe that to magic. I have this weird notion that Elrond's skill comes from being a Half-Elf, i.e., with a great control over his fëa (the spirit) and hröa (the body) like the elves, but with "first-hand" knowledge of
men's bodies and souls. (And
hobbits, it seems

).
Gosh, I'm rambling

.
This train of thought was started by Gandalf's words to
Merry (I think) at the Doors of Durin, that he "once knew all the words used in all the tongues to open doors" (or something like that). Where did he learn that? Surely, in
Aman. Gandalf did not take a crash course in opening spells with
Círdan.
So, we have
Olórin, the wisest of the
Maiar, trying to remember things from his "youth" in Aman, the words used by people to open doors.
Is this a "
Maia power"? Or only a "Maia knowledge"?
I'd say the latter. The same goes for the shutting spell.
In other words, it is not native power; it is knowledge. But how could people use words to command stones or matter in general? Is that not magic? I don't think so. I think that Elves and Dwarves really had a degree of control over matter unimaginable to us. We would call it "magic", a breach of nature's laws, but they wouldn't; to them it is knowledge.
Summing up a somewhat disconnected post:
All instances of "good magic" can be considered as ordinary control of matter by wise beings;
The
Istari, as "veiled Maiar", had no special powers above that; however, they had great knowledge, above and beyond any individual
elf or
dwarf.
All other instances of "intrusive magic" (i.e., intrusive
against nature, and not
along it) are rooted in
evil; or at least in the Elven Rings.