tirse -tir- gismu

x₁ is a quantity of/contains/is made of iron (Fe); [metaphor: strong, durable, tarnishing].

Also (adjective:) x₁ is ferric/ferrous. See also jinme, gasta, molki.

jbovlaste

In notes:

gasta: x₁ is a quantity of/is made of/contains steel of composition including x₂.
jinme: x₁ is a quantity of/contains/is made of made of metal of composition including x₂.
molki: x₁ is a mill/foundry/industrial plant/[assembly line] performing process x₂.
furtirse: t₁=f₁ is a quantity of/contains/is made of rust.