Fire Agate, a variety of chalcedony, is a semi-precious natural gemstone found only in certain areas of northern Mexico and the southwestern United States. It is very rare. I have several pieces of jewelry just listed that are set with this amazing stone. They are all from a private collection. The play of color looks like it is bubbling up in the stone. These "bubbles" are called pinfires. Here are a few, with more photos to come tomorrow.