Cementation in the Oxford English Dictionnary:
METALLURGY:
A process of altering a metal by heating it in contact with a powdered solid, especially a former method of making steel by heating iron in contact with charcoal.
So it is to make it sparks. For security purpose newly made guns were delivered to the Gendarmerie Armory which themself hardened the firizzen to spark.
Very nice pistol Dan!