Gem silica is a form of chalcedony, thought to be the rarest, partially due to such a limited supply. While small amounts of gem silica have been found in southern New Mexico, Mexico, the Philippines, Taiwan, and Peru, most gem silica came from locations near copper mines in Arizona that have now been depleted. When new pockets of gem silica are discovered in copper mines today, only the smaller mines that still use pick and shovel methods of mining can actually extract the gem silica. The larger mines, where the mining procedures are automated, simply destroy the pockets and continue mining copper.
This lovely rare gemstone gets its stunning colors from the presence of the copper, in the same way that turquoise and chrysocolla do, but because gem silica is substantially higher on the Mohs scale of mineral hardness than either of those minerals (gem silica 7 v. turquoise 5ish v. chrysocolla 3ish), it makes for much more durable jewelry.
The stunning color alone would make gem silica one of the most beautiful of all gemstones, but in addition to that, gem silica possesses a translucency that makes it almost appear to glow from within – very magical!