The plate that is used during the Roman Catholic mass as part of the Eucharistic celebration is called a paten. This plate, commonly made out of silver or gold, is used to hold the consecrated hosts, or bread, during communion.
The paten is not used to store unused consecrated hosts, but rather is used only during the communion service itself. A smaller plate, also commonly referred to as a paten, is often used by altar servers to catch any falling crumbs from the host by placing it under the chin of the communicant. Both plates are considered sacred vessels and require special handling and care.