Chrism is essential for the Catholic Sacrament of Confirmation and is prominently used in the sacraments of Baptism, Anointing of the Sick and Holy Orders. These oils are blessed during the Mass of Chrism which takes place in Holy Week before Easter.
Chrism is made of olive oil and is scented with a sweet perfume, usually balsam. Chrism is consecrated by the bishop of the diocese in the presence of the presbyterium at the Mass of the Chrism. The oil of catechumens and the oil of the sick are also blessed at this Mass.
These holy oils are usually stored in special vessels known as chrismaria and kept in a cabinet known as an ambry. When the oils are distributed to a priest for him to use in his ministry they are kept in a smaller vessel with three compartments, known as an "oil stock". There is also a type of oil stock that is shaped like a ring, to make the anointing easier. The "jewel" of the ring is a container with a removable lid.