Refractory Material is material with a high
(essentially, Boiling Point),
thus turns to solid early as it cools.
The opposite is called Volatile Material.
The material in question can be a pure chemical element,
i.e., a Refractory Element or Volatile Element.
A commonly-used line between the two is condensation above/below 1300K.
For example, Iron is moderately refractory and
Lithium is moderately volatile.