The fire opal is characterized by an intense more or less homogeneous color that goes from saffron yellow to orange, up to cherry red. The Mexican opal is water repellent and owes its colors to the presence of traces of iron oxide. For hundreds of years the ancient Mayan and Aztec tribes collected opals near extinct volcanoes. It was called 'Quetzalitzlipyollitli' or 'Bird of Paradise stone' and used in rituals and ornaments. Fire opal is mainly mined in the mines of Mexico while small quantities are also found in Australia and Ethiopia.