"Mr. Baggins!" he cried. "Here is the first payment of your reward! Cast off your old coat and put on this!"
With that he put on Bilbo a small coat of mail, wrought for some young elf-prince long ago. It was of silver-steel which the elves call mithril, and with it went a belt of pearls and crystals. A light helm of figured leather, strengthened beneath with hoops of steel, and studded about the bring with white gems, was set upon the hobbit's head.
"I feel magnificent," he thought; "but I expect I look rather absurd. How they would laugh on the Hill at home Still I wish there was a looking-glass handy!"

(The Hobbit, Chapter 13, Not at Home)

'Also there is this!' said Bilbo, bringing out a parcel which seemed to be rather heavy for its size. He unwound several folds of old cloth, and held up a small shirt of mail. It was close-woven of many rings, as supple almost as linen, cold as ice, and harder than steel. It shone like moonlit silver, and was studded with white gems. With it was a belt of pearl and crystal.
'It's a pretty thing, isn't it?' said Bilbo, moving it in the light. `And useful. It is my dwarf-mail that Thorin gave me. I got it back from Michel Delving before I started, and packed it with my luggage: I brought all the mementoes of my Journey away with me, except the Ring. But I did not expect to use this, and I don't need it now, except to look at sometimes. You hardly feel any weight when you put it on.'
`I should look well, I don't think I should look right in it,' said Frodo.
`Just what I said myself,' said Bilbo. 'But never mind about looks. You can wear it under your outer clothes. Come on! You must share this secret with me. Don't tell anybody else! But I should feel happier if I knew you were wearing it. I have a fancy it would turn even the knives of the Black Riders,' he ended in a low voice.

(LoTR, II-3)

...Bilbo had a corslet of mithril-rings that Thorin gave him. I wonder what has become of it? Gathering dust still in Michel Delving Mathom-house, I suppose.'
`What? ' cried Gimli, startled out of his silence. `A corslet of Moria-silver? That was a kingly gift! '
'Yes,' said Gandalf. `I never told him, but its worth was greater than the value of the whole Shire and everything in it.'
Frodo said nothing, but he put his hand under his tunic and touched the rings of his mail-shirt. He felt staggered to think that he had been walking about with the price of the Shire under his jacket.

(LoTR, II-4)

a huge orc-chieftain, almost man-high, clad in black mail from head to foot, leaped into the chamber; behind him his followers clustered in the doorway. His broad flat face was swart, his eyes were like coals, and his tongue was red; he wielded a great spear. With a thrust of his huge hide shield he turned Boromir's sword and bore him backwards, throwing him to the ground. Diving under Aragorn's blow with the speed of a striking snake he charged into the Company and thrust with his spear straight at Frodo. The blow caught him on the right side, and Frodo was hurled against the wall and pinned.
...
And now what about you, Frodo? There was not time to say so, but I have never been more delighted in my life than when you spoke. I feared that it was a brave but dead hobbit that Aragorn was carrying.'
`What about me? ' said Frodo. 'I am alive, and whole I think. I am bruised and in pain, but it is not too bad.'
`Well,' said Aragorn, `I can only say that hobbits are made of a stuff so tough that I have never met the like of it. Had I known, I would have spoken softer in the Inn at Bree! That spear-thrust would have skewered a wild boar!
'Well, it did not skewer me, I am glad to say,' said Frodo; `though I feel as if I had been caught between a hammer and an anvil.' He said no more.

(LoTR, II-5)

...Gently he stripped off Frodo's old jacket and worn tunic, and gave a gasp of wonder. Then he laughed. The silver corslet shimmered before his eyes like the light upon a rippling sea. Carefully he took it off and held it up, and the gems on it glittered like stars. and the sound of the shaken rings was like the tinkle of rain in a pool.
`Look, my friends!' he called. `Here's a pretty hobbit-skin to wrap an elven- princeling in! If it were known that hobbits had such hides, all the hunters of Middle- earth would be riding to the Shire.'
`And all the arrows of all the hunters in the world would be in vain,' said Gimli, gazing at the mail in wonder. `It is a mithril-coat. Mithril! I have never seen or heard tell of one so fair. Is this the coat that Gandalf spoke of? Then he undervalued it. But it was well given! '
...
`The mail is marvellously light,' he said. `Put it on again, if you can bear it. My heart is glad to know that you have such a coat.

(LoTR, II-6)