Thin sections of rocks which are shown in this gallery are 25 to 30 micrometers thick. They are observed using a polarizing microscope, either in plane polarized light (PPL), or in crossed polars. I particularly like these geological objects. A petrologist (from greek “petros”, the rock) is a scientific who observes, describes, and analyzes rocks in order to understand how they were formed. People visiting this site and wishing to know more about these thin sections (mineralogical composition, conditions of formation, geological context) can contact me or read the books where these watercolors are published.