Durcir belong to the 2
nd group. Durcir is a common french verb.
Durcir is conjugated the same way that verbs that end in :
-ir
Durcir is conjugated with
auxiliary avoir.
Durcir verb is
direct transitive, intransitive.
French verb durcir can be conjugated in the reflexive form:
Se durcir
Durcir verb is a direct transitive verb, so passive voice can be used.