Yuna finishes the golem hunting quest and returns to the royal capital to pick up Fina. Excited, Yuna immediately asks the smithy to make a bunch of mithril knives. Fina finally loses her temper when Yuna casually offers one to Shuri, as well.
The outside is mithril, 
but it's actually lined with iron.
.إنّه ميثريل من الخارج لكنّه داخله من الحديد
Das Mithril ist nur oberflächlich,
im Inneren ist er aus Eisen.