Bartolomé Esteban Murillo, one of the greatest 17th-century Spanish painters, executed The Nativity on obsidian, a lustrous volcanic black glass.
Scholarship suggests that the obsidian was originally created by an Aztec craftsman for use as a "smoking mirror," a ceremonial tool for spiritual communication and divination. Murillo used the Pre-Columbian object as a painting surface, cleverly taking advantage of the vertical inclusions in the glass to suggest heavenly rays shining down on the Holy Family.