Description
The first documented discovery of fire agate took place by C.E. Squires in 1945 or 1946 at Coon Hollow, California in the Oligocene volcanics of the Mule Mountains. The fire agate is found in veins and pockets of a porphyritic andesitic basalt and in an indurated unwelded tuff. The fire agate formed hydrothermally from hot waters saturated with colloidal silica and goethite which invaded cavitites in the volcanics and began to cool. As the solution lost silica through growth, it was periodically adjusted and restabilized when goethite pre-cipitated out of suspension. These solutions were replenished periodically and the cycle repeated, forming Schiller layers of goethite within chalcedony. These iridedescent layers of goethite cause the brililiant interefence colors seen as "fire". The patterns and color combinations are endless and 3 fire agate mines lie in. A series of X-ray diffraction tests were run to determine the iron oxide mineral species and an atomic absorption test to determine total iron oxide content. A petrographic analysis determined the iron oxide to be goethite.
