Fire Agate Ring, size 8
Fire agate and Sterling silver ring.
Fire agate, a variety of chalcedony, is a semi-precious natural gemstone discovered so far only in certain areas of central and northern Mexico and the southwestern United States (New Mexico, Arizona and California). Approximately 24-36 million years ago these areas were subjected to massive volcanic activity during the Tertiary Period. The fire agates were formed during this period of volcanism when hot water, saturated with silica and Iron oxide, repeatedly filled cracks and bubbles in the surrounding rock.