This mask is believed to represent Quetzalcoatl or the Rain God Tlaloc, both associated with serpents. It is made of cedar wood and covered with turquoise mosaic work. The teeth are made of shell. Two serpents, one in green turquoise and one in blue, twist across the face and around the eyes, blending over the nose. Turquoise mosaic feathers hang on both sides of the eye sockets.

This mask is believed to represent the god Tezcatlipoca, one of the Aztec creator gods. He was also the god of rulers, warriors and sorcerers. His name can be translated as 'Smoking Mirror'. In fact, in many depictions during the Post-classic period (A.D. 900/1000-1521) his foot is replaced by a mirror.

The base for this mask is a human skull. Alternate bands of turquoise and lignite mosaic work cover the front of the skull. The eyes are made of two discs of iron pyrites set in rings made of shell. The back of the skull has been cut away and lined with leather. The jaw is movable and hinged on the leather.

This wooden plaque was probably once the central element of a strikingly vivid ceremonial shield. One of the inventories which accompanied the shipments of objects sent to Spain by Hernán Cortés (1485-1547) mentions that sixteen such shields were included.

The plaque is covered with turquoise mosaic, shell and gilded beads. The beads were made of a resinous gum and then coated with gold leaf. A kind of resin was used to secure the mosaic work to the wooden base, although bitumen and wax were sometimes used for this purpose. According to sixteenth-century descriptions, colored feathers were used to decorate the edges of the shields made of stone mosaic work. The holes around this example were probably made for this function.