The Papal Cross is the official emblem of the Catholic Papal office and is only by the Pope.
It is commonly used in jewelry, and because more material is used, jewelers can make more profit from the Papal Cross than from the cross. The three beams represent different things to different people, but some of the interpretations include:
The three crosses on Calvary
The Pope's religious authority in the church, the world and Heaven
The Pope's roles as leader of worship, teacher and community leader
The Pope's roles as Bishop of Rome, Patriarch of the West, and successor of St Peter, Chief of the Apostles
The Papal Cross seems to have been developed by artists and heralds in the latter half of the then recently designated patriarchal cross. It is by now recognizable throughout the world as a symbol of papacy.