Velvety soft blue masses of azurite are formed from the weathering of copper minerals. Used as a pigment by Renaissance painters. Image #3352 4800 X 3200 pixels
Macrophotograph of a small portion of a Cactus quartz (a.k.a. Spirit quartz) crystal cluster with purple amethyst. (Selective focus to place emphasis on the larger amethyst crystal.) The orange coloration is due to iron oxidation and small iron inclusions can be seen in the matrix of many of the crystals. From the Magaliesberg Mountains of South Africa. Image #4117 3200 X 4800
Macrophotograph of a slab of magnesite (white) and hematite (red) from the Globe Copper Mine in Arizona Image #3908 4800 X 3200 pixels
