Vintage Celtic Cross with hidden Prayer Box. Very unusual. Sterling Silver

I don't know how old this is.. I bought it a long time ago at an antique shop. The '925' marking on jewelry signifies that the piece is made of sterling silver. Even the clasp is very pretty. Hidden compartments in old crucifix necklaces were often used to store small religious relics, like fragments of bone or hair from saints, considered "holy relics" by the wearer, allowing them to carry a piece of their faith close to their body; these types of pendants were called "reliquaries" and were particularly prevalent in medieval Europe where people believed relics possessed healing powers. I have found ancient crosses like this for around $10,000... but I'm not sure mine is that old.