A microscope fitted with an analyser and polarizer to allow specimens to be examined in polarized light. The petrological (petrographic) microscope has a light source below the stage so that light can be transmitted through the specimen. It is used to examine thin sections of rocks and minerals. The ore (reflected light) microscope uses an incident light source, allowing light to be reflected from the polished surface of an ore (opaque) mineral. The system of lenses, diaphragms, rotating stage, polarizer, and analyser is broadly similar in both types of microscope, and dual microscopes are available for use with either transmitted or reflected light.