The petrographic microscope is an essential part of any geological laboratory. It is used to recognize minerals, and to describe and classify rocks. A thin section is made from the rock sample, with a piece is mounted on a glass size and cut and ground down to a slice 0.03 mm thick. Our ZEISS Axioscope 5/7/Vario installation is a new generation microscope with perfect optics and ergonomics. It allows for observation in transmitted and reflected visible and ultraviolet light at 50x to 1000x magnification. A high-resolution CCD color camera allows for photographic documentation of the samples. Advanced digital image processing can be used for distortion-corrected mosaic imaging, depth of field correction, and numerical analysis of microscope images.