Semi-precious materials such as this often associated with a particular geographical region and highly valued because of their rarity. Many of the religious objects were portable, as were the small portraits. They were often made near to the source of the material and then taken elsewhere. St James the Greater (Santiago) was the patron saint of Spain. His shrine at Santiago de Compostela was the goal of many pilgrims, hence he is shown wearing a pilgrim’s hat and carrying a staff.
The prime function of jets seems to have been to signify that pilgrims had completed their journeys, and reached the shrine of St James at the Cathedral of Santiago de Compostela, which pilgrims did over the course of six hundred years, from the twelfth to the eighteenth century. Many seem to have formed beads of rosaries. In structure jet is a particularly dense type of coal, and can be carved and polished. Medicinal and indeed magical qualities were thought to be inherent in the substance from earliest times. Jet is found in different parts of Europe (as well as North America), but the two richest regions are the Asturias in northern Spain, and Whitby, Yorkshire, in North East England.