Magic.
Det låter som ett ansiktssvar, men det är det inte. När vi presenterar spegeln kallar Galadriel Sam tidigare omtale av "Elf-magi":
'And you?' [Galadriel] said, turning to Sam. 'For this is what your folk would call magic. I believe; though I do not understand clearly what they mean; and they seem also to use the same word of the deceits of the Enemy. But this, if you will, is the magic of Galadriel. Did you not say that you wished to see Elf-magic?'
Fellowship of the Ring Book II Chapter 7: "The Mirror of Galadriel"
Tolkien hänvisar till denna passage (snett) i den osedda bokstaven 155, när han talar om de olika typerna av magi i sin värld (betonar hans):
I suppose that, for the purposes of the tale, some would say that there is a latent distinction such as once was called the distinction between magia and goeteia. Galadriel speaks of the 'deceits of the Enemy'. Well enough, but magia could be, was, held good (per se), and goeteia bad. Neither is, in this tale, good or bad (per se), but only by motive or purpose or use.
[...]
Their magia the Elves and Gandalf use (sparingly): a magia, producing real results (like fire in a wet faggot) for specific beneficent purposes. Their goetic effects are entirely artistic and not intended to deceive: they never deceive Elves (but may deceive or bewilder unaware Men) since the difference is to them as clear as the difference to us between fiction, painting, and sculpture, and 'life'.
The Letters of J.R.R. Tolkien 155: To Naomi Mitchison (draft). September 1954
Om spegeln är en magi eller en goetisk effekt, är det tydligt att det produceras av Elvish "magi".
Spegeln visas inte i någon annan skrifter av Tolkiens, och ingen av hans tidiga utkast till kapitlet berör det i någon stor detalj, så det handlar om det bästa vi kan göra.
Vi kan göra en intressant jämförelse med palantíri 1 , som också gjorts av älven. Även om de fungerade mer som teleskop än Galadriels spegel, så kunde de se de flesta händelser överallt i världen:
The vision of the palantíri was not "blinded" or "occluded" by physical obstacles, but only by darkness; so they could look through a mountain as they could look through a patch of dark or shadow, but see nothing within that did not receive some light. They could see through walls but see nothing within rooms, caves, or vaults unless some light fell on it; and they could not themselves provide or project light.
Unfinished Tales Part 4 Chapter III: "The Palantíri"
Och Gandalf antyder att de också kan användas för att se igenom tiden (fet är min betoning, kursiv är Tolkiens):
'Each palantír replied to each, but all those in Gondor were ever open to the view of Osgiliath. Now it appears that, as the rock of Orthanc has withstood the storms of time, so there the palantír of that tower has remained. But alone it could do nothing but see small images of things far off and days remote. Very useful, no doubt, that was to Saruman; yet it seems that he was not content. Further and further abroad he gazed, until he cast his gaze upon Barad-dûr. Then he was caught!
[...]
And how it draws one to itself! Have I not felt it? Even now my heart desires to test my will upon it, to see if I could not wrench it from him and turn it where I would - to look across the wide seas of water and of time to Tirion the Fair, and perceive the unimaginable hand and mind of Fëanor at their work, while both the White Tree and the Golden were in flower!' He sighed and fell silent.
The Two Towers Book III Chapter 11: "The Palantír"
Även om vi inte vet hur de gjordes (förutom att de gjordes av Fëanor, Galadriels farbror), indikerar den en prioritet för den typen av magi.
1 Hat-tip till Hjortjägare för att föreslå jämförelsen