One of the most fascinating uses of obsidian in Aztec (Mexica) culture was the creation of large obsidian mirrors that were polished on both sides and used in shamanic rituals and prophecy. These mirrors were used as a medium of divination and were often called “smoke” or “spirit” mirrors. Diviners would gaze into the shifting and shadowy black obsidian and would see into the future as well as visit the past.