• 13.037 It was of silver-steel,

…which the Elves call mithril.

I am fascinated to learn that silver steel has its own, albeit unhyphenated, sub-entry.

silver steel  n. a fine steel containing a small amount of silver.

1831   J. Holland Treat. Manuf. Metal I. 248   Silver steel, having the advantage of euphony.., becomes a popular denomination in the market.

“silver, n. and adj.” OED Online, Oxford University Press, June 2017, http://www.oed.com/view/Entry/179788. Accessed 21 September 2017.