Cantera Opal is a gemstone formed from Rhyolite, which is a kind of igneous rock. When magma cooled on the earth surface, traces of gas and steam escaped from the stone, leaving cavities. Eventually, opal would form within these volcanic rock cavities, creating what we know as Cantera Opal. 
Fire opal is believed to fill your soul with joy and happiness. One only has to look to the opal, enjoy the colors and fire to help release the flow of your emotions and give you feelings of warmth and harmony.