Argentinean ceramics were traditionally finished in a fogata, or an open pit fire. This art, which originates from the northern provinces, was used to create a range of objects - from functional cooking vessels and water jugs to ceremonial ornaments, such as sacred urns. This piece is painted with cobalt oxide. Cobalt-based pigments, derived from minerals in the Earth's crust, have been used since ancient times. Medieval miners believed that mischievous spirits, called kobalds, stole silver from the mines, leaving behind seemingly worthless ore. It was discovered that the mineral in this ore creates a beautiful blue color when exposed to heat; the name stuck. Cobalt, today, is name after these spirits.