Opal fires All the rainbow colorsOpal fires come from the cristaline structure of the opal: micro-spheres of hydrated silice. When the micro-spheres have all the same size, the light is diffracted in a color depending on this size.
Different types of opals Many typesAustralian Opals : black opals, cristal opals, boulder opals,light opals, matrix opals, opal doublets, opals triplets... Fire opals : from Mexico or Brasil Ethiopian opals : same under categories as Australian opals. Opales communes : they can be found in all countries, green, blue, pink, white dendritic... Their colors come from pigments and not light diffraction
