Here are some pictures of ore minerals taken under reflected light. This differs from the previous rocks, which were taken in transmitted light. The difference is that metallic minerals can’t be cut thin enough to allow light to pass through, unlike the common rock-forming minerals in the previous photos. To study metallic ore minerals, light is reflected off the polished mineral surface and reflected to your eye. The colors aren’t usually as striking as the silicates and other minerals observed in transmitted light. In reflected light, most minerals look gray! But the eye can be trained for subtlety. Why use a microscope when technology can identify mineral compositions and ore grades? Because only the microscope can help you study mineral textures such as grain interlocking, which is important to determine how much breaking and processing will be required to separate the ore from the host rock.

Click here to return to the first page

Click here to return to photos of rocks

Click here to see more rocks and stories