He wears a beautiful detailed halo with a star on the top. The Golden Legend (an ancient history of saints) states that at his baptism when his godmother held him over the font, she saw a star shining on his forehead that would illuminate the whole world. Because of this, he is typically pictured with a star above him, and he has also become the patron saint of astronomers.
He wears the hooded robes of the Dominican order of monks, which he founded in 1215. St Dominic is also frequently shown holding a rosary. Legend states that the St Dominic was moved to create the rosary when he beheld a vision of the Blessed Virgin Mary. Some scholars dispute this since the rosary did not become a popular devotion until the 15th century, but many believe that St Dominic definitely did encourage the use of some form of the rosary in his preaching and missionary work.
Around the edge the medal is inscribed "Saint Dominique P.P.N" The name Dominic is given the French spelling, and the abbreviation "P.P.N" stands for "Priez Pour Nous" which means "Pray For Us".