Fire opal stones are created by fire, true to their name. It is believed that the depths of extinct volcanoes are where these Mexican opals occur.
When water penetrates into the silica-enriched lava and fills its seams and hollow places, the result is a fire opal. The lava encased the water inside itself due to the volcano's intense heat and pressure. The sun-bright red orange fire opal stones would eventually appear.
The Aztec and Mayan cultures held these stones in great respect. Fire opal stone was referred to as quetzalitzlipyollitli, which roughly translates to "the stone of the bird of paradise."