Sauron famously defied lightning on Numenor-arguably, lightning is more hotter
than lava.
The lava isn't what destroys the One Ring- it's the power Sauron has invested
in his furnace. By dropping the One into the lava, Frodo (or Gollum)
effectively forces Sauron's power to feed on itself, imploding it and
nullifying his existence. The Sammath Naur is where Sauron's power is
greatest-even Galadriel's phial is put out there. Any other lava is hot, but
not invested with Sauron's power at all. The Ring has to be, in a way destroyed
by Sauron himself wihtout him knowing it. Hence the fires of Mt Doom, where his
power is highest are the only logical solution.
As Elrond says in the movie,no craft posessed by the Men,Elves or Dwarves in
the Council could destroy it; Sauron was absent, of
course.
There is but one task remaining in Arda-we,the Dragons of Valinor will make it happen.
Lone resident of the Republic of Gondor
PO-TA-TOE-S not PO -TAH-TOE-S!
