The main purpose of "Crelling's Petrographic Atlas of Coals and Carbons" is to show what coals, cokes, chars, carbons, graphites, and other natural and man-made carbonaceous materials look like under the optical microscope with the intent of characterizing these materials for both scientific and industrial applications.
Most of the photomicrographs were taken through an optical microscope at high magnification (200x to 500x) using oil immersion objectives. All were taken in reflected white light with and without the use of a polarizer, an analyzer, and a retarder plate. In some cases, the photomicrographs were taken in fluorescent light using ultra-violet illumination.
The photomicrographs were selected to show the most common structures and textures as well as inclusions of various kinds. At this time seven "chapters" are available. However, additional chapters including vitrinite macerals, liptinite macerals, inertinite macerals, anthracites, thin sections, and dispersed organics are now being planned and prepared.
Please cite this website and photomicrographs herein as follows:
Crelling, J.C., and Rimmer, S.M., 2015, Crelling's Petrographic Atlas of Coals and Carbons. Southern Illinois University Carbondale. https://coalandcarbonatlas.siu.edu/ (Date accessed).