Extreme macro photograph of amethyst from the Purple Haze mine near Thunder Bay, Ontario, Canada. The red coloration is due to the presence of hematite inclusions. Image #3015
Velvety soft blue masses of azurite are formed from the weathering of copper minerals. Used as a pigment by Renaissance painters.; #3352
Linear patterns in a thunderegg agate from Oregon. Thundereggs are nodule-like rocks and are found in layers of rhyolitic lava flows. Image #3701
