The two reclaimed by Sauron are pity and fame. Thraíns ring is luck. Two of the lost ones are ardor and splendor.
Where is it said that exactly four of the rings were destroyed by fire and only three retrieved? The only thing I found in Silmarillion is that "some" of them were destroyed by dragons, but no specific number is given.
- In The Lord of the Rings (Book I, Ch. 2, "The Shadow of the Past"), quite soon after having read the runes of the One Ring at Bag End, Gandalf says to Frodo: "Seven the Dwarf-kings possessed, but three he has recovered, and the others the dragons have consumed." --Tik 22:22, 28 November 2013 (UTC)