An amice is a vital part of the Armor of God (Eph. 6.). Though it is a simple piece of white cloth it represents the Helmet of Salvation; and, like any helmet when engaging in battle, it is essential in the spiritual battle a priest must face when approaching the altar to say Holy Mass.
It is made (preferably) with linen and has long strands of solid weave cotton tape attached at the top two corners. It is worn across a priest's shoulders and around his neck with the purpose of covering the priest’s cassock and collar so they are not visible once his alb is on. The strands wrap around the back and tie in front at the waist.
Before the priest places the amice on his shoulders he touches it to the top of his head and recites the following vesting prayer:
Impone, Domine, capiti meo galeam salutis, ad expugnandos diabolicos incursus.
Place, O Lord, upon my head the helmet of salvation, that I may repel the assaults of the enemy.
Recently a priest approached me to ask if I could make an amice for him at a specific size and weight. I was very happy to take on this task and fashion a proper Helmet of Salvation.
It was an interesting exercise for me. The entire time I was making the amice I had images of forging a helmet a priest would wear into battle. I never imagined myself a blacksmith; I lack the strength and stamina for such work but Smith was my great-grandfather's name. Perhaps those long-forgotten roots live on in some small way through this work. It is interesting to ponder and, as always, an absolute joy to serve our Lord and His Church this way.