Fire agate is one of nature's most exquisite phenomenal stones. Chemically, fire agate consists of platy crystals of an iron mineral over layers of chalcedony. When cut and polished the rainbow of colors of the iridescent layers appear, giving an intense flashing fire of breathless beauty.

The chemical formula is SiO2. Colors are usually brown base with iridescence hues of red, green, orange, yellow, gold and rare blue and violet. Luster is waxy. Surface can be "grape-like" forms or "botryoidal". Flashes of colors are observed as gem interacts with light. The more instense colors, the more valuable it is.

The more directional display of colors as stone is rotated, the more it is appreciated. There are only a few kind of stones in the gemstone Kingdom that shows all the colors of the spectrum in one stone. They are opal, ammonites and labradorites (spectrolites). The "flashes of fire" ranges from instense to the subdued and can be absolutely captivating!