Suite101: Magic by Melkor, No Returns Accepted - How did magic work in Middle-earth, and was it really as unlimited as some people believe?
Here is a brief excerpt:
Why gold? I've had that question put to me a few times now. Where on Earth did I get the idea that dragons might draw power from gold, or, more specifically, that there was something special about gold when it came to magic?
Well, I neglected to mention one crucial paragraph when I was citing Tolkien's essay (which, by the way, Christopher Tolkien called "Notes on motives in the Silmarillion" -- the Morgoth-element paragraphs were lifted from near the end of section ii).
When last we referred to Tolkien's view on how the magic worked for Sauron, he had said: "...Morgoth's power was disseminated throughout Gold, if nowhere absolute (for he did not create Gold) it was nowhere absent. (It was this Morgoth-element in matter, indeed, which was a prerequisite for such 'magic' and other evils as Sauron practised with it and upon it.)"
But what follows explains my fascination with gold, and why I think dragons might have been able to sustain themselves upon it:
It is quite possible, of course, that certain 'elements' of conditions of matter had attracted Morgoth's special attention (mainly, unless in the remote past, for reasons of his own plans). For example, all gold (in Middle-earth) seems to have had a specially 'evil' trend -- but not silver. Water is represented as being almost entirely free of Morgoth. (This, of course, does not mean that any particular sea, stream, river, well, or even vessel of water could not be poisoned or defiled -- as all things could.)
So, there is no specific dragon connection but Tolkien did at least give some thought to gold's peculiar place in the hierarchy of what we could call "magical substances" in Middle-earth. Gold is a fascinating element. It's the third most conductive metal we know of (only copper and silver being more effective). In it's purest form gold can be safely eaten (although gold bouillion is quite expensive, I'm told) though it has no real nutritive value for us. Dragons may or may not have benefitted from soaking up some ounces.
Of course, it's been pointed out to me that a dragon's hoard included more than just gold. Smaug's belly, for example, was encrusted with jewels. That's true. But anyone who has seen the picture of Bilbo and Smaug which Tolkien painted for The Hobbit (titled "Conversation with Smaug") cannot fail to notice that the bulk of the dragon's bed is made of gold. Yes, there are all sorts of sparkly things scattered across the pile (including an Arkenstone atop the heap) but most of the treasure was gold.
Now, that's not to say jewels cannot be special in their own right. Recall how Ungoliant lusted after the gems Melkor stole from the Noldor at Formenos. She ate all but the Silmarils and grew more powerful as she did so. These gems could not possibly have contained what Tolkien referred to as the Morgoth-element, even though Melkor had been held in Aman for a very long time. So, the question arises of whether there was some other "magic" element that Ungoliant was feeding upon, or if she was simply feeding on the essence of the gemstones themselves.
When Ungoliant sucked the life from the Two Trees and then drank the liquid light from the Wells of Varda she grew to an immense size. She became so large and powerful that Melkor feared her. Light was Ungoliant's sustenance, but the light of the Two Trees was the product of what might be deemed "pure magic", the power of a Vala. Yavanna had brought the Two Trees to life by the power of her song, an act of sub-creation within the Halls of Ea which was unequalled, and which she claimed she would never be able to repeat. Thus fed by the power of Yavanna's greatest enchantment, Ungoliant became huge and even more powerful than before.
Likewise the stolen gems of the Noldor were enchanted. Feanor had learned how to make gem-stones which glowed under the starlight, or which glowed of their own accord. He had many years in which to build up a great treasury, and this treasury was moved to Formenos when Feanor, Finwe, Feanor's sons, and the Noldor who followed them settled there far in the north of Valinor during the period of Feanor's banishment from Tirion. So Ungoliant was able to feed not only upon the essence of the Noldorin jewels but also the power Feanor (and any other crafters) had put into them.
If the Noldor were able to create magical gems in Aman, they were no less able to create them in Middle-earth.
Follow the link below to read the entire essay.