This is the matter that deals with the study of rocks, their minerals and their textures, at a microscopic level.
Petrography studies and describes the weaving of rocks and their minerals, optically analyzes the minerals and the microstructures it presents.
Mineralogy studies the crystals, the structure and the chemical - physical characteristics of the minerals, therefore it investigates the hardness, the optical properties and the magnetic ones
Paleontology studies fossils at the microscopic level. With thin sections you can study fossil bones, teeth, corals, but also biological samples such as animal excrement and gallstones.