Macro photograph of the detail in Birds Eye rhyolite; a rock of volcanic origin Image #2371 3200 X 4800 pixels
Macro photograph of a slab of fluorite (calcium fluoride) from the Jiangxi Province in China Image #2509 5906 X 4912 pixels
Blue masses of azurite are formed from the weathering of copper minerals. Used as a pigment by Renaissance painters. Image #2278 3033 X 4329 pixels
