All relics have miraculous power from the point of view of Christianity since a particular saint is physically present in them. Their function is to form a link between heaven and earth since the saint's body is present on earth and his soul, dwelling in the kingdom of God, can intercede with God for all who ask for help through prayers.
The origin of the cult of relic worship goes back to the very roots of Christianity. We distinguish the difference between primary and secondary relics. Primary relics include the relics of saints (the authentic remains of an individual). However, these may not only be bones but also teeth, hair, blood, and pieces of skin. Secondary relics are objects that the saints have been in contact with or touched.
In early Christianity, reliquaries were likely chests, clay vessels, or tombs of saints. It is essentially a container for the relics of the saints. However, it must be remembered that, from the point of view of faith, the relics are always more valuable than the box itself.
Over time, reliquaries have changed according to current trends. We can see, for example, a reliquary in the shape of a hand, a leg, or even a bust (depending on the part of the saint's body that was kept). Relics were also placed in small personal medallions, paintings, monuments, or altars. The materials from which the reliquaries are made are meant to express the preciousness and value of the relics.
They are mostly objects made of gold, silver, or gilded copper. The decoration of reliquaries has always reflected the time in which they were created. Mostly we encounter decorations with goldsmith techniques (filigree, enamels, jewel stones). These are amazing and very valuable works of art.