is a variety from colourless to yellow, orange and red; for the top qualities we find also with play of colours. As any opal, the greater the play of colours the higher the price. This stone increase in value every year; we are talking about Mexican type. Also Brazil produce fire opal but has no play of colours and is less valuable. Handle this stone with care, due to his low hardness (6-6.5), like any other opal must avoid strong heat and attention on setting.This stone has a good play of color on his rhiolitic matrix.