[Legate of Amon Lanc]

Originally Posted by Alfirin

First a question, since all of the rings of power are accounted for at the beginning of the LOTR (the nine men's are on the nazgul, the seven dwarves are in sauron's keeping the three eleven are on Elrond's Gladriel's and Gandalf's fingers and the one is in Frodo's keeping) how exactly does anyone know that dragon fire will melt the lesser rings?

Well, "it is said", says Gandalf - it may not be true. However, you are not right about the Seven Rings of Dwarves. Sauron recovered only (darn, I never remember whether he recovered three and four remained or he recovered four and three remained), who cares, some of them, and the rest was consummed by the dragons. Here you go.

Originally Posted by Alfirin

But I beive tolkein said that some dragons could also breathe Green flames. Since fire does not, under normal circumstaces burn green (unless the dragons were eating a LOT of copper salts) I think that those flames may have had some sort of additonal power and could be considered "magic" in some manner."

I believe you are referring to this:

Originally Posted by The Hobbit

he soared blazing into the air and settled on the mountain-top in a spout of green and scarlet flame

Yes, this seems the most "magic" part of all. Though, who knows what happened inside the dragon's belly - but it was not a "normal" fire in any case. Btw, I'm not that knowledgeable on this field, but isn't the colour here saying something about the temperature? Ee, in case of gases probably not, huh?