This is a very rare French Immaculate Heart Of Mary reliquary ex voto. Inside, a relic to Saint Amantius Episcopal.
You can find Sacred Heart reliquaries pretty easily, but to find a magnificent Immaculate Heart Of Mary reliquary with a crown of roses and a sword piercing the heart is few and far between.
This reliquary will soon be part of an assemblage necklace, so keep a weather eye on the Metal Corset horizon....